+" Lycopodiaceae."
+
+
+
+ | TABLE OF CONTENTS. |
+ xii |
+
+
+ | TABLE OF CONTENTS. |
+
+
+ | TRIVIATION FROM THE CYANOPHAEAE TO THE PHAEOPHOREAE |
+ |
+ 284 |
+
+
+ | Lateral Generations of the Cyanophyceae |
+ |
+ 284 |
+
+
+ | Sexual Generation; Fertilization |
+ |
+ 285 |
+
+
+ | DIVISION IV. GYMNOSPERMÆ. |
+ |
+ 285 |
+
+
+ | Class I. CYCADACE (Cycadae) |
+ |
+ 286 |
+
+
+ | 2. Cycadace (Pine-Trees) |
+ |
+ 285 |
+
+
+ | Family I. Cycadace |
+ |
+ 286 |
+
+
+ | 2. Pinolidae |
+ |
+ 287 |
+
+
+ | Class II. Gymnospermae |
+ |
+ 290 |
+
+
+ | 1. Female Gymnospermae |
+ |
+ 271 |
+
+
+ | DIVISION V. ANGIOSPERMÆ. |
+ |
+ 273 |
+
+
+ | Class I. MONOCOTYLEDONIUM |
+ |
+ 274 |
+
+
+ | Family I. Halimionaceae |
+ |
+ 279 |
+
+
+ | 1. Halimionum - |
+ |
+ 283 |
+
+
+ | 2. Spadiceform - |
+ |
+ 297 |
+
+
+ | 3. Eucalyptus - |
+ |
+ 308 |
+
+
+ | 4. Eucalyptus - |
+ |
+ 309 |
+
+
+ | 5. Seismium - |
+ |
+ 309 |
+
+
+ | | 310 | 311 | 312 | 313 | 314 | 315 | 316 | 317 | 318 | 319 | 320 | 321 | 322 | 323 | 324 | 325 | 326 | 327 | 328 | 329 | 330 | 331 | 332 | 333 | 334 | 335 | 336 | 337 | 338 | 339 | 340 | 341 | 342 | 343 | 344 | 345 | 346 | 347 | 348 | 349 | 350 | 351 | 352 | 353 | 354 |
+
+
+
+Sub-Class I. Charophytaeum
Family I. Balleforiaceae
2. Querciforium
3. Juglandiforium
4. Querciforium
5. Polygoniforium
6. Liriodendron
7. Castelletum
8. Polyparionum
9. Rhododendron
10. Rhododendron
11. Clusiiform
&nb...
+
+xii
+
+
+
+ | TABLE OF CONVENT. |
+ Page |
+
+
+ | Sub-Class 3. Sproutacidae |
+ |
+ |
+ 304 |
+
+
+ |
+ J. Pentacellicus |
+ |
+ 306 |
+
+
+ | Family 36. Bicorniae |
+ |
+ |
+ 306 |
+
+
+ |
+ " |
+ |
+ 287 |
+
+
+ |
+ " |
+ |
+ 511 |
+
+
+ |
+ " |
+ Tetracongulina |
+ 511 |
+
+
+ | Family 37. Tetracongulinae |
+ |
+ |
+ 511 |
+
+
+ |
+ S. Personatam |
+ |
+ 517 |
+
+
+ |
+ " |
+ Nunifera |
+ 541 |
+
+
+ |
+ " |
+ Bulbosa |
+ 541 |
+
+
+ |
+ " |
+ Bulbosa |
+ 246 |
+
+
+ |
+ " |
+ Campasumilum |
+ 550////////////////////////////////////////)8
+
+2 CLASSIFICATION OF THE VEGETABLE KINGDOM.
+
+bundles. The lowest Mosses have, however, a thallus. Fertilisation is accomplished by means of self-mitosis, spirally coiled spermatoidons, through the agency of water. From the fertilised oosphere a "fruit-body" (capsule) with unicellular organs of reproduction arises ; this pericarp gives rise to the vegetative system, which bears the organs of sexual reproduction ; and this system is divided into two stages—the prothallus, and the leaf-bearing plant produced on it.
+
+Alternation of generations :
+
+I. The prothallus and the entire nutritive system which bears the organs of sexual reproduction.
+II. The capsule-like sporangium, with spores.
+3 Classes : 1. Bryophytes.
+2. Mucil. Lentin. Mosses.
+
+Division III.—Pteridophyta or Vascular Cryptogams,
+Fern-like Plants having leaf-bearing shoots, true roots, and vascular bundles with tracheides and sieve-tubes. Fertilisation as in the Mosses. From the fertilised oosphere the leaf-bearing shoot arises, which bears on its leaves the reproductive organs, the spores, and the capsule-like sporangium. Upon the germination of the spore a small prothallus is formed, which bears the sexual reproductive organs.
+
+Attention of generations :
+
+1. Prothallus with organs of sexual reproduction.
+2. Leaf-bearing shoot with capsule-like sporangia.
+
+3 Classes : 1. Filicinae, True Ferns.
+2. Equisetinae, Horsetails.
+3. Lygodinae, Club-mosses.
+
+Division IV.—Gymnospermae. The vegetative organs are in the main similar to those in the 3rd Division; special shoots are modified into flower-stalks bearing cones. From the fertilised oosphere, which is fertilised by means of the pollen-tube, the leaf-bearing plant is derived ; this passes the first period of its life as an embryo in the seed, and continues its development when the gametophyte dies off. The pollen-grains are similar to those corresponding to the spores of the two preceding Divisions, are called respectively the pollen-grain and embryo-axe. The pollen-grains are multifoliar; i.e. they contain an indistinct prothallium. In the embryo-axe a prothallium, rich in reserve material (endosperm),
+
+CLASSIFICATION OF THE VEGETABLE KINGDOM.
+3
+
+with female organs of reproduction, is developed before fertilisation. The pollination is carried by means of the wind to the ovules; these are enclosed in the ovaries, and are situated on the open fruit-leaf (carpet), which has no stigma.
+
+Alternation of generations:
+I. Plant-forms with two stamens in ovule.
+II. Leaf-bearing plants, with flowers which produce the pollen-sac and ovule.
+
+3 Classes: 1. Cycadeae.
+2. Coniferae.
+3. Gnetaeae.
+
+Division V. Angiospermae. The members of this group are very similar to those of Division IV. The ovules are, however, enclosed in closed fruit-leaves (ovary), which have a special portion (stigma) adapted for the reception and germination of the pollen-grain. The pollen-grains are bicellular, but with only a membrane separating the two cells; one cell is directed towards the stigma by animals (chiefly insects), by the wind, or by some other means. Endosperm is not formed till after fertilisation. Alternation of generations in the main is that in the Gymnosperms, but less distinct ; while the sexual generation, the protogynous, with the organs of fertilisation in the same leaf, is more common.
+
+2 Classes: 1. Monocotyledonae. Embryo with one seed-leaf.
+2. Dicotyledonae. Embryo with two seed-leaves.
+
+For a long time the vegetable kingdom has been divided into Caryophyllae (so called because they contain seeds in a cup-like receptacle), and Phanerogamae or Flowering-plants which have evident sexual organs.
+
+The first three divisions belong to the Caryophyllae, and the third and fourth divisions to the Phanerogamae. This arrangement has no systematic value, but is very convenient in many ways.
+
+The first division is known as Spore-plants, since they multiply by unicellular organs (spore), and the Phanerogamae in contradistinction are called Seed-plants (Spermatophyta), since they multiply by seeds, multicellular bodies produced by the fusion of two gametangia (spore). The first division includes in its infancy, Mosses, Ferns, and Gymnosperms are together known as Archeophyta, while their powers in common a female organ of distinct structure, the Archegonium.
+
+3 See Angiospermae.
+
+4
+
+THALLOPHYTA.
+
+DIVISION I
+
+THALLOPHYTA.
+
+The thallus in the simplest forms is unicellular; in the majority, however, it is built up of many cells, which in a few instances are exactly similar; but generally there is a division of labour, so that certain cells undertake certain functions and are constructed accordingly, e.g., the cells of the thallus may be divided into conducting structures, vessels or similar high anatomical structures, or seldom formed, and the markings on the cell-wall are with few exceptions very simple. The Myxomycetes occupy quite an isolated position, and masses of non-division are naked masses of protoplasm (plasmodium).
+
+As regards the external form, the thallus may be entirely without special prominences (such as branches, members), but when such are present they are usually of a definite origin and growth, that is, disregarding the hair-structures which may be developed. A shoot of a Seaweed or of a Lichen, etc., is essentially any other part of the plant; only among the highest plants (Chlorophyta) certain Sporangia, Spermogonia, and other Red Seaweeds do we find some differences between the various external organs of the plant body as between stem and leaf, so that they must be distinguished by these names.
+
+*Roots* of the same structure and development as in the Secl-
+plants are not found, but *organs of attachment* (rhizoids and lamina) serve partly the bodily functions of the root.
+
+SYSTEMA TYPIUM OF THE THALLOPHYTA includes the Thallophytes belonging to the sub-divisions: Slime-Fungi, Algae and Fungi.
+Formerly the Thallophytes were divided into Algae, Fungi, and Lichens. But this last group must be placed among the Fungi,
+since they are composed of Fungi, which live symbiotically with Algae.
+The Slime-Fungi must also be placed among the Fungi as a distinct sub-division. The *Alga* is a colouring substance,
+which is generally green, brown, or red, and by means of which they are able to obtain their organic nutrition from carboxic acid and water.
+The Bacillariophyta form a distinct group within the Algae in this respect; like the Fungi and Slime-Fungi they have as a rule no such colouring material, but must have organic car-
+bonaceous food; those plants form no starch, and need no light
+
+MYXOMYCETES. 5
+
+for their vegetation (most Fungi require light for fructification). The Myxomycetes, Bacteria, and Fungi derive their nourishment either as saprophytes from dead animal or vegetable matter, or as parasites from living animals or plants (hosts), in which they very often cause disease.
+
+A remark, however, must be made with regard to this division. Among the higher plants no means exists to halt the vegetative process until death has taken place. In the case of the Algae (Chlorophyta), a parasitic, is placed among the Conjugatinae, Noctuia and Conularia, saprophytes, belong to the Conjugatinae, and are found in the soil. In the same manner there are some ciliates parasitic or saprophytic forms among the Algae, and these must be laid upon the fact that not only the Blue-green Algae, but also the Green Algae, are parasitic on other organisms. The Blue-green Algae group, Siphonoclora. The reason for this is that cytometric classifications must be based upon the relationship of form, development, and reproduction, and from this point of view it appears that the Blue-green Algae are a subdivision of the entire group of Fungi. All the Thallophytes, which are designated Fungi (when the entire group of Fungi is considered), are included in the blue-green form (Fizymycetes) and are therefore classified as Algae. But probably through them has taken its origin from the Algae; the blue-green algae being a subdivision of the Fungi. The distinction of colour referred to is therefore not the only one which separates the Algae from the Fungi, but it is almost the only characteristic mark by which we can distinguish between these two groups of organisms.
+
+The first forms of life on earth were probably "Protista," which had assimilating matter in or on other words, they were Algae because they could absorb food from their surroundings. These were followed by those which belong to the simplest forms of all plants. Fungi and Slime-Fungi must have appeared later, because they are dependent on other plants which assimilate food.
+
+Sub-Division I—MYXOMYCETES, SLIME FUNGI.
+
+The Slime-Fungi occupy quite an isolated position in the Vegetable Kingdom, and are related to those which are most nearly related to the group of Rhinopods in the Animal Kingdom. They live in and on organic remains, especially rotten wood or leaves, etc., on the surface of which their sporangia may be found.
+
+They multiply by means of spores, which in the true Slime-Fungi grow into mycelium. According to recent investigations of Wasmann's mode micro-organisms (Nitzschia) have been found in these fungi. Such hypothesis that the first organisms must necessarily have contained chlorophyll is therefore untenable.
+
+I Myxogastera, Engler's Syllabus, p. 1.
+
+6
+
+MYXOMYCETES.
+
+are produced in sporangia, but in some others free. The spores are round cells (Fig. 1 a) which in all the true Slime-Fungi are surrounded by a cell-wall. The wall bursts on germination, and the contents float out in the water which is necessary for germination. They move about with swimming and hopping movements, and are provided with a cell-nucleus and a pulsating vacuole. Later on
+
+![]() A series of images showing the development of "Fuligo" from spore to Myxamoeba, each one magnified 300 times; m is a Myxamoeba of Egypto epedemica; Phymo Myxamoeba of Pigeon's alveolus; and Myxamoeba of the sea.
+
+FIG. 1.--A Development of "Fuligo" from spore to Myxamoeba ; each one magnified 300 times; m is a Myxamoeba of Egypto epedemica; Phymo Myxamoeba of Pigeon's alveolus; and Myxamoeba of the sea.
+
+they become a little less active, and creep about more slowly, while they continue to alter their form, shooting out arms in various places and drawing them in again ($g$, $h$, $i$, $k$, $l$, $m$); in this stage they are called Myxamoebae.
+
+The Myxamoeba is a plant whilst taking up nourishment from the material in which it lives, and multiplies by division. At a later stage a larger or smaller number of Myxamoebae may be seen to
+
+6
+Acreaen and Pitcomorphorales, Ibd.
+
+MYXOMYCETES.
+7
+
+oculose and form large masses of pteleophan, plasmodia, which in the "Flowers of Tain" may attain the size of the palm of a hand, or even larger, but none of them are smaller. The plas-
+modia are independent, cream-like masses of protoplasm, often containing grains of carbonite of lime and colouring matter (the infarctus), and are very active.
+
+They creep about in the decaying matter in which they live, by means of amoeboid movements, internal streamings of the pro-
+
+A. Four sporangia of Sirovitsa jaceae, fixed on a branch of the plant.
+
+
+Fig. 2.—The plasmodium (a) of Sirovitsa jaceae, com-
+mencing to form into sporangia (b). Down on July 8th. The sporangia (c) are seen at different stages of their
+life next morning ; e shows the development of their
+toplam continually taking place; finally they creep out to the surface, and very
+often attach themselves to other objects,
+such as Mosses, and form sporangia (Fig.
+3). These are usually cylindrical (Fig. 3), spherical
+or pear-shaped (Fig. 4); they rarely attain
+a larger size than that of a pin's head, and
+are red, brown, white or yellowish with a very delicate wall.
+
+In this way may be found a " Capillitium" (Fig. 4 op.), or net-
+work of branch-like fine strands between the spores. Flowers of
+
+
+B. Sporangium of Ar-
+chidium candidum.
+(a) open ; p wall of sporangium ;
+(b) closed.
+
+
+S
+ALGAE.
+
+Tan (Fulgo spinos) has a fruit-body composed of many sporangia (see Althamium), which has the appearance of flat, irregular, brown cakes, inside the fragile external layer of which a loose powder, the spores, is found. It generally occurs on heaps of farmers' bark, and appears somewhat similar to Fulgo spinos, but that material is used, and is destructive by spreading itself over the bark and choking them.
+
+All the motile stages may pass into resting stages; the small forms only survive these without a wall, but the large ones at the same time divide in addition into polyhedral cells. When favourable conditions arise, the walls dissolve and the whole appears again as a naked (free-moving) mass of protoplasm.
+
+To the following genera belong: *Fulgo* spinosus, *Fulgo* spinosus, *Bryonema*, *Pleurococcus*, *Stenocaulon*, *Lycogala*, *Fulgo*, *Sporosira*, *Eotricaria*.
+
+Some genera wanting a sporangium-wall belong to the Slime-Fungi : *Cronartium*, whose fruit-body consists of polygonal plates, and is covered with a slime-like substance; and in the swarm-stage is wanting and which has stalked spores. *Phaeomorphophora braeica* prevails upon the roots of cabbages and other cruciferous plants, causing large swellings. *Pl. alba* causes severe ailments among root-growth on the roots of various plants. *Phylogymna leptophylla* may be found as small knobs (tubercles) on the roots of liraginuous plants. It is still uncertain whether it is this Funicus or Bacteria which is the cause of the formation of these tubercles.
+
+Sub-Division I. — ALGAE.
+
+**Mode of Life.** The Algae (except most of the Bacteria) are themselves able to form their organic matter by the splitting up of the carbonic acid contained in the water, or air in some cases, and for this purpose need light. The majority live in water, fresh or salt, but many are present on damp soil, stones, bark, etc., and in soil.
+
+With the exception of the Bacteria, no saprophytes have actually been determined to belong to this group, and only very few true parasites are known (e.g., *Pseudomonas*, *Algeria*, etc.), but good many are found epiphytic or endophytic on other algae or water plants, and on animals (for instance, certain Schizophryes and Protococcoides; Trichophyton weickeri in the hairs of Brugmansia and the Sthoth), and several species in symbiotic relation to various
+
+
+
+Fungi (species of Lichens), to Sponges (e.g. *Tentacellosa georgiop-
+pala*, *Spongia delimitata*), and toundry Fungi and other
+lower animals as Radiolaria, Hyphae, etc. (the so-called *Zoocystella*
+and *Zoanellites*, which are perhaps purely stages in development
+of various Green and Brown Algae).
+
+**Vegetative Organism**. The cells in all the Algae (excepting
+certain unicellulars) are surrounded by a membrane which
+(with the exception of the Bacteria) consists of pure or altered
+cellulose, sometimes forming a gelatinous covering, at other times
+a harder one, with deposits of chalk or albumen formed in it. The
+membrane is often called the *plasmalemma*. In the Schizomycetes,
+which are unicellular, may be one or more (e.g. *Hydrodictyon*, *Nephthea*) in each cell. Except-
+ing in the majority of the Bacteria, colour materials (of which
+chlorophyll, or modifications of it, always seems to be found) occur
+in the cytoplasm, but not in the nucleus. In the higher Algae the cell-
+nucleus, as in most of the coloured Schizophytes or are con-
+tained in certain specially formed small portions of prodephasm
+(chromatophores).
+
+The cells divide at a certain stage of development consist only
+always of only one cell; by its division multicellular individuals
+may arise, or, if the daughter-cells separate immediately after the
+division, as in many of the simplest forms, the individual will,
+during its further growth, become a multicellular organism with a single
+cell (unicellular Algae). In multicellular individuals the cells
+may be more or less firmly connected, and all the cells of the
+individual may be exactly alike, or a division of labour may take place between them. The form of the cells is variable, and are
+constructed accordingly; this may also occur in parts of the cell
+in the large unicellular and multicellular Algae (Nephthea, p. 62).
+
+The cells in most of the Algae belong to the parenchymatous form;
+those in some few to the collenchymatous form; and those in some
+somewhat oblong; in many Algae (particularly Fucoidae and Florideae)
+occur, moreover, Apkys-like threads, which are very long,
+often branched, and are either formed of a single cell, or, more
+frequently, of several cells united by their walls into a coenocytic growth.
+The parenchymatous as well as the hyphal-like cells
+may, in the higher Algae (especially in certain Fucoidae and
+Florideae) be first differentiated, so that they form well-
+defined and histologically distinct systems of tissue, e.g., assimilating,
+conducting, storing, and mediating.
+
+With regard to the external form, the thallus may present no
+
+10
+A.G.E.
+
+differentiation, as in many multicellular Algae, or in multicellular Algae of the lower order, which are then either equally developed in all directions (e.g. Pleurococcus, Fig. 47), or form flat cell-plates (Mesophyllum) or threads (Ocularia, Fig. 21). The first step in the way of differentiation is the formation of a stem, leaf, shoot and base (Ricciaria, Porphyra); but the division of labour may proceed so that differences may arise between vegetative and reproductive cells (Eudogium, Fig. 54); hairs and organs of attachment being formed on one side of the plant, while the leaves at roots, are developed, and even leaves in certain forms of high order, belonging to different classes (e.g. Caulerpa, Fig. 50; Chironia, Fig. 61; Sargassum, Fig. 72; and many Florideae).
+
+The second step in differentiation is the formation of spores, in many instances, simply by division into two, and more or less complete separation of the divided product (Diatomeae, Desmidiaceae (Fig. 36), many Fucus-plants, etc.), or by detached portions of the thallus being set free as gametes (e.g. Rhodomonas, Rhodochloris, phycomyce, small filaments known as hormogonia are set free), or asexually by special reproductive cells (spores) set free from the thallus; these may be either stationary or motile. The stationary reproductive cells are called zoospores (e.g. Rhodochloris), and the motile ones (trapsores of the Floridean), or may possess a cell-wall; in the latter case they may be formed directly from the vegetative cells, generally by the thickening of the walls (kaikoule), or only after a process of division has taken place. The zoospores are either akinetes, as well as akinetes, may either germinate immediately or may become resting-cells, which germinate only after a period of rest.
+
+The spore-leaf reproductive cells are spherical, egg- or pear-shaped bodies (Fig. 58), which are produced by budding off from other cells (cooperation), and propel themselves through the water by means of cilia; or they are Pgylo-amoebae, which have no cilia and creep on a substratum by means of pseudopodia. The cilia, when present, are usually situated at the pointed end (though however, from the membrane), are mostly situated at the pointed and colourless end, which is directed forwards when in motion, and are 1 to 4 (Fig. 63 B), 4 or more. Both the cilia in the Brown Algae are usually situated at the pointed end (Fig. 64 A), and are usually situated in a circle round the front end (Eudogium, Fig. 6 A, and Desmoea), or are very numerous and situated in pairs dis-
+tributed over a large part or nearly the whole of the sporocarp (Yezkoria). Besides being provided with one or more nuclei
+
+A.C.E.
+11
+
+(Fanacheta), they may also have a red "eye spot" and vacuoles, which are sometimes pulsating, etc. They appear and reappear at certain intervals. The swampsperes move about in the water in irregular paths, and apparently quite voluntarily, revolving round their longer axes; but they come to the surface, and then remain there until they are attacked by their dependence on light, or driven by some passing mass of food material.
+
+The swampsperes germinate, each forming a new plant, as their movements show. They surround themselves with a cell-wall, grow, and then divide into two parts, one of which is in the condition of germination, and about to attach themselves by means of the front end, which has been developed into haptera (see also Fig. 5 B, lowest figure).
+
+**Fig. 5.** Swampsperes germinative. A The lower cells are full of swampsperes, while the upper ones are empty. The greater part have escaped through the aperture m. of the cell-walls.
+
+**Fig. 6.** - Germinating swampsperes.
+
+The sexual reproduction here, probably in all cases, consists in the coalescence of two masses of protoplasm, that is, in the fusion of their nuclei.
+
+The swampsperes reproduce from autotomous conjugation, or isogamous fertilisation, and is characterized by the fact that the two coalescing cells (termed gametes) are equal, or almost equal, in shape and size (the female gamete in the Oultericon, e.g. Zanzaridinæ)
+
+![]()
+A: A close-up view of a swampsperes germinating.
+B: A close-up view of a swampsperes germinating.
+C: A close-up view of a swampsperes germinating.
+D: A close-up view of a swampsperes germinating.
+E: A close-up view of a swampsperes germinating.
+F: A close-up view of a swampsperes germinating.
+G: A close-up view of a swampsperes germinating.
+H: A close-up view of a swampsperes germinating.
+I: A close-up view of a swampsperes germinating.
+J: A close-up view of a swampsperes germinating.
+K: A close-up view of a swampsperes germinating.
+L: A close-up view of a swampsperes germinating.
+M: A close-up view of a swampsperes germinating.
+N: A close-up view of a swampsperes germinating.
+O: A close-up view of a swampsperes germinating.
+P: A close-up view of a swampsperes germinating.
+Q: A close-up view of a swampsperes germinating.
+R: A close-up view of a swampsperes germinating.
+S: A close-up view of a swampsperes germinating.
+T: A close-up view of a swampsperes germinating.
+U: A close-up view of a swampsperes germinating.
+V: A close-up view of a swampsperes germinating.
+W: A close-up view of a swampsperes germinating.
+X: A close-up view of a swampsperes germinating.
+Y: A close-up view of a swampsperes germinating.
+Z: A close-up view of a swampsperes germinating.
+AA: A close-up view of a swampsperes germinating.
+AB: A close-up view of a swampsperes germinating.
+AC: A close-up view of a swampsperes germinating.
+AD: A close-up view of a swampsperes germinating.
+AE: A close-up view of a swampsperes germinating.
+AF: A close-up view of a swampsperes germinating.
+AG: A close-up view of a swampsperes germinating.
+AH: A close-up view of a swampsperes germinating.
+AI: A close-up view of a swampsperes germinating.
+AJ: A close-up view of a swampsperes germinating.
+AK: A close-up view of a swampsperes germinating.
+AL: A close-up view of a swampsperes germinating.
+AM: A close-up view of a swampsperes germinating.
+AN: A close-up view of a swampsperes germinating.
+AO: A close-up view of a swampsperes germinating.
+AP: A close-up view of a swampsperes germinating.
+AQ: A close-up view of a swampsperes germinating.
+AR: A close-up view of a swampsperes germinating.
+AS: A close-up view of a swampsperes germinating.
+AT: A close-up view of a swampsperes germinating.
+AU: A close-up view of a swampsperes germinating.
+AV: A close-up view of a swampsperes germinating.
+AW: A close-up view of a swampsperes germinating.
+AX: A close-up view of a swampsperes germinating.
+AY: A close-up view of a swampsperes germinating.
+AZ: A close-up view of a swampsperes germinating.
+BA: A close-up view of a swampsperes germinating.
+BB: A close-up view of a swampsperes germinating.
+BC: A close-up view of a swampsperes germinating.
+BD: A close-up view of a swampsperes germinating.
+BE: A close-up view of a swampsperes germinating.
+BF: A close-up view of a swampsperes germinating.
+BG: A close-up view of a swampsperes germinating.
+BH: A close-up view of a swampsperes germinating.
+BI: A close-up view of a swampsperes germinating.
+BJ: A close-up view of a swampsperes germinating.
+BK: A close-up view of a swampsperes germinating.
+BL: A close-up view of a swampsperes germinating.
+BM: A close-up view of a swampsperes germinating.
+
+12
+
+**ALGAE**
+
+**ciliaria**, Fig. 7, is considerably larger than the male gamete). The cell in which the gametes are developed is called a *gametangium*, and the reproductive cell formed by their union—which generally has a thick wall and only germinates after a short period of rest—is termed a *zygote* or *zygospore*. The conjugation takes place in two ways:
+
+(v) In the one way the gametes are motile cells (planktonic, zoospores), i.e., they swim in pairs during their swarming hither and thither in the water; during this process they first touch each other (Fig. 8 a), generally at first touching to the clear anterior end, and after a time they coalesce and become a zygospore (Fig. 8 b), which surrounds itself with a cell-wall (Fig. 8 c).
+
+This form of conjugation is found in *Ulothrix* and other Algae (Fig. 45, 56, 60).
+
+(b) Among other Algae (e.g. *Diatomeae* and *Conjugatae*), the conjugating cells continue to be surrounded by the cell-wall of the mother-cell (*aplospore*); the
+
+![]()
+A: A motile cell (zoospore)
+B: A motile cell (zoospore)
+C: A motile cell (zoospore)
+D: A motile cell (zoospore)
+E: A motile cell (zoospore)
+F: A motile cell (zoospore)
+G: A motile cell (zoospore)
+H: A motile cell (zoospore)
+I: A motile cell (zoospore)
+J: A motile cell (zoospore)
+K: A motile cell (zoospore)
+L: A motile cell (zoospore)
+M: A motile cell (zoospore)
+N: A motile cell (zoospore)
+O: A motile cell (zoospore)
+P: A motile cell (zoospore)
+Q: A motile cell (zoospore)
+R: A motile cell (zoospore)
+S: A motile cell (zoospore)
+T: A motile cell (zoospore)
+U: A motile cell (zoospore)
+V: A motile cell (zoospore)
+W: A motile cell (zoospore)
+X: A motile cell (zoospore)
+Y: A motile cell (zoospore)
+Z: A motile cell (zoospore)
+AA: A motile cell (zoospore)
+BB: A motile cell (zoospore)
+CC: A motile cell (zoospore)
+DD: A motile cell (zoospore)
+EE: A motile cell (zoospore)
+FF: A motile cell (zoospore)
+GG: A motile cell (zoospore)
+HH: A motile cell (zoospore)
+II: A motile cell (zoospore)
+JJ: A motile cell (zoospore)
+KK: A motile cell (zoospore)
+LL: A motile cell (zoospore)
+MM: A motile cell (zoospore)
+NN: A motile cell (zoospore)
+OO: A motile cell (zoospore)
+PP: A motile cell (zoospore)
+QQ: A motile cell (zoospore)
+RR: A motile cell (zoospore)
+SS: A motile cell (zoospore)
+TT: A motile cell (zoospore)
+UU: A motile cell (zoospore)
+VV: A motile cell (zoospore)
+WW: A motile cell (zoospore)
+XX: A motile cell (zoospore)
+YY: A motile cell (zoospore)
+ZZ: A motile cell (zoospore)
+
+
+
+**Fig. 8.—Ulothrix zoosporæ; a portion of a thread with zoosporæ, of which two are formed in each mother-cell. The zoosporæ are shown in different stages of development. I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, XIII, XIV, XV, XVI, XVII, XVIII, XIX, XX, XXI, XXII, XXIII, XXIV, XXV, XXVI, XXVII, XXVIII, XXIX, XXX, XXXI, XXXII, XXXIII, XXXIV, XXXV, XXXVI, XXXVII, XXXVIII, XXXIX, XL, XLI, XLII, XLIII, XLIV, XLV, XLVI, XLVII, XLVIII, XLIX, L, LI, LII, LIII, LIV, LVII, LVIII, LXI—LXIV. Ia—IVa—IVb—IVc—IVd—IVe—IVf—IVg—IVh—IVi—IVj—IVk—IVl—IVm—IVn—IVo—IVp—IVq—IVr—IVs—IVt—IVu—IVv—IVw—IVx—IVy—IVz—Vaa—Vaab—Vaac—Vaad—Vaabe—Vaabf—Vaabg—Vaabh—Vaabi—Vaabj—Vaabb—Ia—Ib—Ic—Id—Ie—If—Ig—Ih—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir—Ii—Ij—Ik—Il—Im—In—Io—Ip—Iq—Ir-Iii-Iiv-Ivi-Ivj-Ikv-Ilw-Iix-Iiy-Iiz-Ilia-IIib-IIic-IIid-IIje-IIkf-IIkg-IIlh-IIji-IIkj-IIkk-IIlj-IIkl-IIlk-IIll-IIml-IImn-IIno-IIpp-IIpq-IIqr-IIrs-IIss-IItu-IItv-IIuw-IIvx-IIwy-IIxz-IIIaa-IIIab-IIIac-IIIad-IIIae-IIIaf-IIIag-IIIah-IIIai-IIIaj-IIIak-IIIal-IIIam-IIIan-IIIao-IIIap-IIIaq-IIIar-IIIas-IIIbt-IIIct-IIIdd-IIIde-IIIdf-IIIge-IIIhh-IIIhi-IIIij-IIIjk-IIIkl-IIIll-IIIma-IIImb-IIImc-IIImd-IIIme-IIImf-IIImg-IIImh-IIImi-IIImj-IIImk-IIIml-IIImm-IIImo-IIImp-IIImq-IIImr-IIIms-IIImt-IIInu-IIIod-IIiee-IIiff-IIigg-IIihh-IIijj-IIikk-IIill-IIimmm-IIinii-IIjnjj-IIikkk-IIilll-IIimmm-IIinii-IIjnjj-IIikkk-IIilll-IIimmm-IIinii-IIjnjj-IIikkk-IIilll-IIimmm-IIinii-IIjnjj-IIikkk-IIilll-IIimmm-IIinii-IIjnjj-IIikkk-IIilll-IIimmm-IIinii-IIjnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-Iikkk-Iilll-Iimmm-Iinii-Ijnjj-iikkk-iilll-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii-injj-iikkk-illl-immm-inii—in jj-iikk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-limm-lnn-j-jk-kk-lill-
+
+
+**Fig. 9.—Ulothrix zoosporæ; a portion of a thread with zoosporæ of which two are formed in each mother-cell. The zoosporæ are shown in different stages of development. Ia–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–Iv–
+
+**Fig. 10.—Ulothrix zoosporæ; a portion of a thread with zoosporæ of which two are formed in each mother-cell. The zoosporæ are shown in different stages of development. Ia – Ib – Ic – Id – Ie – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa – IIb – IIc – IID – IIe – If – Ig – Ih – IIa -
+
+A.I.G. 13
+
+Aplanogametangia generally grow out into short branches, which lie close together and touch one another, the wall at the point of contact then dissolved (Fig. 30). Through the aperture thus formed, the aplanogametes unite, as in the first instance, and form a rounded zygote, which immediately surrounds itself with a cell-wall. Various modifications occur; compare Figs. 37, 38, 41, 43.
+
+The highest form of the sexual reproduction is the Egg or Oogamous fertilization. The two coenocytic cells are in the main alike each other in form, well as in size. The one which is con-
+tained in the egg-cell is known as the egg-spermatozoon (spermatozoa), develops as a rule a large numbers in each mother-cell (autolysis).
+
+![]() A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
+Fig. 30.—Fertilization in the Helioblastum (Pseus reticulatus).
+
+diem); they are often self-
+mottle (except in the Flori-
+dian species, which are named
+sporophores), and are some-
+times smaller than the other
+kind, the female, which is
+known as the egg-cell
+(sporophore). The egg-cell is
+always a motionless, spherical,
+primordial cell which can either float about freely in the
+water, as in the Fucusia (Fig. 9), or is surrounded by a cell-wall
+(孢子囊), generally only one sporophore is to be found in each
+oogonium, but several occur in Sphagnum (Fig. 10). The re-
+
+14
+A.G.R.
+
+silt of the spermatocorm coalescing with the egg-cell is, as in the preceding case, the formation of a zygote, which generally undergoes a period of rest before germination (the Florideae are an exception, a fruit-body, cytopsyr, being produced as the result of coalescence.)
+
+An excentric fertilization is effected by the Algæ. Sphaerocoryne (Fig. 8). The filamentous thallus is formed of cylindrical cells with many vacuoles (r in A); some cells divide egg-cells (B), others spermatocysts (C), the latter in a parenchymatous layer. The egg-cells are surrounded by a cell-wall or a club-elongate paracyste with two ellips at the front end (G). It is however a swimmers. The spermatocysts come from their cells through apertures in the wall of the paracyste. The spermatozoa swim out through these apertures. The columnar end of the spermatocorm is united at first with the "re- sive spout" of the egg-cyst (H). Then the formation of a zygote with water takes place (I).
+
+The female (parthenogenetic) or male (androgenic) sexual cell may, sometimes without any preceding fertilization, form a new individual (e.g. *Ulotheca somata*, *Ojentrocarpus*, etc.).
+
+**Systomata** **divisoria** of the Algæ. The Alge are divided into the following classes:
+
+1. **Syngeneutaceae**, Dinoecellulaceae, or Peridinaceae. 3. Diatom-
+aceae; 4. Scourghitidae, Fissos.-ageae; 5. Conjugatae; 6. Chloro-
+phyceae, Gymnox.-ageae; 7. Chlorella, Stenostyphus; 8. Phycophyceae;
+9. Dictyotales; 10. Rhodophytae.
+
+Among the various forms of the Algæ, the Syngeneutaceae, the Dinoflagellata, and the unicellular Volvocinean (Chlamydomonade), distinct transitional forms are found approaching the animal kingdom, which can be grouped as animals or plants according to their mode of life, taking food or other characteristics. Only an artificial boundary has been drawn between the animal and vegetable kingdoms. In the following pages only those forms which possess chromatophores, and have no mouth, will be con-
+sidered as Algæ.
+
+Class I. **Syngeneutaceae**.
+
+The individuals are uni- or multi-cellular, free-swimming or motionless. The cells (which in the multicellular forms are loosely connected together, often only by mucilaginous envelopes) are naked or surrounded by a mucilaginous cell-wall, in which silicon is never embedded. They contain one cell-nucleus, one or more pulsating
+
+STENOGONIA.
+vacuoles, and can to two hand, or plate-like chromatophores with a brown or yellow colour, and sometimes a greenish hue.
+
+Reproduction takes place by vegetative division, or axenically by zoospores, akinetes (or aplanospores?). Sexual reproduction is un-
+known. They are all fresh water forms.
+
+To this class may perhaps be assigned the recently arranged and very little known genus *Stenogonia* (Dichotomocera), which partly occur in the free condition in the sea, in the so-called "sea-eggs", and which are symbiotic in various lower marine animals.
+
+The *Sympathecium* are closely re-
+lated to certain forms in the animal
+kingdom, as the Flagellate.
+
+Order I. Chrysoomonadinae. In
+divisional stages, the cells, remain-
+ing in free condition, naked or sur-
+rounded by a multinucleated covering.
+The cell is usually ovoid or ellipsoid,
+2 (rarely only 1) cilia, almost of the same length, and generally with a radial "eye-spot" at their base, and with 3 (rarely 2) nuclei. The division of the individual cells either during the streaming, or during a resting stage, is effected by liberation of one or more cells, which in the latter case are connected together.
+
+A. Unicellular: Chrysoamonas, Cryptomonas, Micromonas, Neoproteus.
+
+B. Multicellular: *Chrysochromatium*, *Chrysochromatium*.
+
+Among the unicellular Chrysoomonadinae are probably classified some forms which are only stages in the development of the multinucleate, or of other species.
+
+Order II. Chrysopyaceae. Are unicellular, and differ mainly from the pre-
+ceding in being attached either on a slime-thread (Spilis-
+thrix), or on a stalk (Eucyamnus).
+
+They have two cilia, and multiply by longitudinal (Gymnodinium) or transverse (Chrysophyceae) division of one of the daughter-individuals (zoospore). Division may also take place in a motilecute stage (pseudocyst-stage).
+Only one nucleus is present in each cell. The cells are gen-
+tially attached, uni- or multi-cellular; each individual cell is distinctly contractile, and fixed at the bottom of a gelatinous sheath.
+
+Fig. 15.—Sympathecium: the multi-
+nucleate individual is surrounded by a
+multinucleated granular envelope.
+
+Order III. *Sympathecium*. The cells are attached to each other by means of a
+gelatinous sheath. The cells are multinucleate; they are
+contractile, and move by means of cilia. They are
+planktonic organisms.
+
+*Sympathecium*, *Dimorphom**
+
+16
+
+**DINOFLAGELLATA.**
+
+Order 4. **Hydracria.** The individuals are attached, without cilia, multi-
+cellular, branched, and with apical growth. The cells are spherical, but in the final stage they become elongated, and finally break up into multinucleate. Asexual reproduction by zoospores which are tetrahedral, with 1 cella, and by resting akinetes. *Hydracria* is common most in mountain brooks.
+
+Class 2 **Dinoflagellata.**
+
+The individuals are of a very variable form, but always uni-
+cellular, and floating about in free condition. The cell is dorsi-
+central, bilateral, asymmetrical and generally surrounded by a colour-
+less membrane, which has no stolae embedded in it, but is formed of a substance which is more or less transparent. The body is rectan-
+gularly provided with pores and raised borders, easily breaks up into irregularly-shaped pieces. In the forms which have longitudinal and cross furrows, two cells are fixed where these cross each other, and project their anterior extremities towards the front of the body perpendicu-
+larly and is directed longitudinally to the front or to the rear, the other one stretches acrosses and lies close to the cell, often in a narrow (cross furrow). The chromatophores are coloured brown or green. In some cases they are yellowish or orange-coloured. They are radially placed, discs, which sometimes may coalesce and become a star-shaped chromatophore. The colouring material (pyrophyll) consists, in addition to a modification of chlorophyll, also of phycoglycine and phycoside. The food is obtained by the products of assimilation which consist of yellow, red or colourless oil (?) and starch. Cell-nucleus one: In *Pseudofulvella* several nuclei are found; contractile vacuoles many, which partly open in the ciliae (?). (Fig. 10.) In some case oocytes, coloured red by haematochrome. For the *Pyrophyllinae* see pagenote in *Euglenida.*
+
+The reproduction takes place as far as known at present,
+only by division. This is many times the form that takes
+place in the swarming condition, and in that case, is always
+parallel to the longitudinal axis. The daughter-individuals, each of which retains half of the original shell, sometimes do not separate
+at once from each other (Fig. 11), but remain connected (e.g., Fig.
+12). In this case several connected individuals may be formed. In others,
+the division occurs after the cilia have been thrown off and the cell-om-
+tentis rounded. The daughter-cells then adoptively new cell-walls.
+A palaeola-la-stage (motional division-stage) sometimes appears to
+
+DUXOPLACELLA. 17
+
+take place, and also phaneropores (?) with one or two burn-like elongations (e.g. in *Peridinium cinctum* and *P. tubulatum*); at germination one, or after division two or more new individuals may be formed.
+
+Sexual reproduction has not been observed with certainty.
+
+The Bacteria move forward or backward, turning round their longitudinal axes; in their motion they are influenced by the action of light. The motion possibly may be produced only by the transverse cilia, which vibrate rapidly; whilst the longitudinal cilium moves slowly, and is supposed to serve mainly for the appearance that they live principally in salt water, but also in fresh.
+
+Besides the coloured forms, which are not dependent on their own organic compounds by the splitting up of the carbonic acid contained in the water, there are a few colourless forms (e.g. *Gymnodinium*, etc.), or those which possess chromatophores (*Pelagia*); these appear to live saprophytically, and may be able to absorb solid bodies with which they come into contact.
+
+Diatomaceae are found in the "Plankton" of the open sea, where they form together with Diatomaceae the basis for the known life. It is known that every community that lives in the sea is furnished with food (like the Nautilius, which belongs to the animal kingdom and to which they are perhaps related) produce light, known as bioluminescence.
+
+Diatomaceae (*Cyclotella, Cyclotilium*) are allied through their lowest form (Cyclocyclus) to the Synechococcus, which have no chloroplasts. They may be divided into three orders.
+
+Order I. *Cyclotella*. With numerous and generally longitudinal furrows. Many radially placed, disc-forming chromatophores. The most common genera are:
+
+- *Cyclocyclus* (Fig. 13), *Peridinium*, *Gymnodinium*, *Dinophysis*, *Chlorodinium*, *Pelagia*.
+- With several transverse furrows, no chromatophores, and several chlorophylls. Only one genus: *Pelagia*.
+
+![]() A diagram showing the structure of a diatom cell.
+Fig. 13.—A diatom cell.
+18 A. The cell wall with its various
+19 ails. B from behind: 1st transverse
+20 furrow; 2nd transverse furrow;
+21 chloroplasts; e starch; y reticulum;
+22 C cytoplasm from the vesical
+23 membrane; d nucleus; f longitudinal
+24 furrow; g chloroplast; h chlorophyll; i
+25 transverse furrow; p chloroplasts
+26 within the vesicle; q longitudinal
+27 furrow; r chloroplasts within the
+28 vesicle; s chlorophyll; t chloroplasts
+29 within the vesicle; u chlorophyll; v
+30 transverse furrow; w chloroplasts
+31 within the vesicle; x chlorophyll; y
+32 transverse furrow; z chloroplasts
+33 within the vesicle; a chlorophyll;
+
+Order II. *Pelagia*. With several transverse furrows, no chromatophores, and several chlorophylls. Only one genus: *Pelagia*.
+
+Order III. *Gymnodinium*. With numerous and generally longitudinal furrows. Many radially placed, disc-forming chromatophores. The most common genera are:
+
+- *Cyclocyclus* (Fig. 13), *Peridinium*, *Gymnodinium*, *Dinophysis*, *Chlorodinium*, *Pelagia*.
+- With several transverse furrows, no chromatophores, and several chlorophylls. Only one genus: *Pelagia*.
+
+Order IV. *Gymnodinium*. With numerous and generally longitudinal furrows. Many radially placed, disc-forming chromatophores. The most common genera are:
+
+- *Cyclocyclus* (Fig. 13), *Peridinium*, *Gymnodinium*, *Dinophysis*, *Chlorodinium*, *Pelagia*.
+- With several transverse furrows, no chromatophores, and several chlorophylls. Only one genus: *Pelagia*.
+
+18
+DIATOMEE.
+
+The order *Pseudodinacea* deviates to a high degree from the other Dinoflagellata, not only by its many transverse furrows, each with its own transverse ellipsoid, and by the absence of a median furrow, but also by the presence of a second kind of flagellum, which otherwise does not occur within the whole class. It may therefore be questionable whether this order should really be placed in the vegetable kingdom.
+
+Class 3. Diatomacee.
+
+The individuals of this class are unicellular organisms, assume very various forms and may be unicellular or multicellular, but present no differentiation; many similar cells may be connected in chains, embedded in mucilaginous masses, or attached to mucilaginous stalks. The cells are usually disc-shaped, elliptical or oval, slightly dipcentral and have no cilia; those living in the sea condition have the power of sliding upon a firm substratum. The cell contains 1 cell-nucleus and 1–2 plate-shaped or several disc-shaped chloroplasts. The latter contain a large amount of chlorophyll, in addition to a modification of chlorophyll, a brown colouring matter, diatomin. 1 or 2 pyrenoids sometimes occur. Starch is wanting and the first product of assimilation appears to be a kind of oil.
+
+The cells are impregnated with silica to such a degree that they are imperishable and are therefore able to contribute in a great measure to the formation of the earth's crust. The structure of their cut-edges is most peculiar and differs from that of plants (except for the *Chlorophyceae*, which do not possess a single nucleus, but is made up of two—the "shells"—compare *Eucnella* and *Proconchium* among the Dinoflagellata) which are fitted into each other, on one side forming a kind of hinge-like joint, like a box with its lid (Fig. 14 B). The two parts which corre-
+19spond to the bottom and lid of the box are known as valves.
+Along the central line of the valves a longitudinal rib may often be found, interrupting at its course into a small cleft (perichora homologous with the perichora of the Dinoflagellata), through which the protoplasm is enabled to communicate with the exterior (Fig. 14 A). It is principally by reason of the valves, which bear numerous, transverse striae, strim or warts, etc. (Figs. 14, 16, 17), that the Diatomaceae are easily distinguished from other algae as test objects in microscopical science. When the division takes place, the two shells are separated a little from each other, and after the cell-contents have divided into two masses, two new shells are formed, one fitting into the larger valve, the other one
+
+Diatomeae. 19
+
+into the smaller valve of the original frustule. The latter cell (frustule) is thus, upon the whole, smaller than the mother-cell, and as the cells do not increase in size, some frustules are smaller than the ones fructifying, and these are produced by repeated division; it follows that smaller and smaller frustules are pro-
+duced. This continued diminution in size is, however, compensated for by the fact that the valves of those have been reduced to a certain minimum, of anapogres, 2–3 times larger. These may easily be recognized by the
+prolapse of a cell inclosing, round-
+ing off and surrounding itself with a
+new wall (e.g. Meloira) or after con-
+jugation, which may take place with
+various degrees of difficulty. Indi-
+viduals unite after the secretion of a
+quantity of mucus, and the valves then commence to separate from each other, so that at first the two indi-
+viduals turn towards each other. The
+
+Fig. 14.—Pinacodermis: $R_1$ from
+the edge, shows the valves fitting
+together; $A$, a valve.
+
+Fig. 15.—Various Diatomaceae: A Diatoma vulgaris. B Nitzschia expansa. C Nitzschia
+tenuis (internal view). D Gonyaulax ascerticula (external view). E Nitzschia ussii
+(external view).
+
+protoplasmic bodies now release themselves from their cell-wall,
+and each rounds off to form an ellipsoidal mass; these two pro-
+
+20
+Diatomeae.
+
+toplasmic masses (gametes) coalesce to form a zygote, the cell-
+nuclei and chromatophores also fusing together. The zygote in-
+creases in size, and surrounds itself with a firm, smooth, siliceous
+wall—the perizonium. The auxospores, whichever way they arise,
+are not resting stages. The germination of the zygotc com-
+mences by the expulsion of the protoplast from the wall, which
+is cell-wall and constructing first the larger valve, and later on
+the smaller one; finally the membrane of the zygotc bursts (e.g.
+Haustratium). 2. The conjugation occurs in a similar manner,
+but the zygotes are not formed into two daughter-cells, but by
+conjugation into two daughter-cells. Those lying opposite one
+another conjugate (Fig. 16) and form two zygotes. The for-
+mation of the perizonium, and germination take place as in the
+preceding instance (e.g. *Euplottia*). 3. Two cells placed close-
+to each other, and one of the two effecntons,
+
+![]() A B C D
+
+Fig. 16.—Conjugation of *Cymbella varicella*. A, The protoplasts in the two cells be-
+dividing into two masses; B those masses coalesce in pairs; the cells (f) coalesced in a
+massive condition; C, D, Two cells placed close together.
+
+without coalescing, becomes an auxospore. The formation of
+the wall takes place as in the preceding case. This is found in
+the Naviculaceae, and in the *Complanaceae* (e.g. *Fratellina,
+Coconoea*).
+
+The Diatomaceae may be found in salt water as well as in fresh water
+(when in such masses that the colour of the water or mud becomes
+yellow or brown); in the same manner the genera *Chetoneura,
+Elodeococcus, Coscinodiscus*, and several others, form large silime-
+masses, "Phankton" on the surface of the sea), on damp soil and in dust. In fresh water they are often found in great accumu-
+lations, often in large deposits (siliceous earth, mountain
+meal), as in the cement lime in Jutland, the alluvial deposits
+beneath Berlin, in clay strata beneath peat bogs, in grano, etc.
+
+DIATOMEAE.
+21
+
+These accumulations of fossilized diatoms are used in the manu-
+facture of dynamite and in various manufactures.
+
+The Diatomeae appear nearest to, and must be placed as a group co-ordinate with the Dinoflagellata, as they doubtless may be supposed to derive their origin from forms resembling *Eucariota*, an hypothesis which is supported by the numerous analogies which are striking in many respects, can only be conceived as analogies, and cannot be founded upon homologies, and it is therefore impossible to regard them as proof of genetic relation-
+ship. The family contains only one order.
+
+Order 1. Diatomacea. This order may be divided into two sub-orders, viz:
+
+Sub-order 1. *Placochromatica*. The chromatophores are discoid, large, 1 or 2 in each cell; the structure of the valves is bilateral and always without reticulate markings. The follow-
+ing groups belong to this sub-order: *Gonophyenea*, *Cymbulites*, *Anachrysis*, *Pleurophycus*, *Pleurocystis*, *Pleurostomus*, *Pleurostomoides*, *Anaphthropus*, *Nitzschia*, *Surinamia*, and *Emotion*.
+
+Sub-order 2. *Coccochromatica*. The chromatophores are granular, small and many in each cell. The structure of the cells is similar to that of the preceding sub-order. The following groups belong to this sub-order: *Fragilaria*, *Meridion*, *Tubellaria*, *Lemnophora*, *Biddulphus*, *Anguliferus*, *Repullosa*, *Coccolodaceae* and *Melosira*.
+
+![]()
+A: A species of diatom.
+B: A species of diatom.
+C: A species of diatom.
+D: A species of diatom.
+E: A species of diatom.
+F: A species of diatom.
+G: A species of diatom.
+H: A species of diatom.
+I: A species of diatom.
+J: A species of diatom.
+K: A species of diatom.
+L: A species of diatom.
+M: A species of diatom.
+N: A species of diatom.
+O: A species of diatom.
+P: A species of diatom.
+Q: A species of diatom.
+R: A species of diatom.
+S: A species of diatom.
+T: A species of diatom.
+U: A species of diatom.
+V: A species of diatom.
+W: A species of diatom.
+X: A species of diatom.
+Y: A species of diatom.
+Z: A species of diatom.
+AA: A species of diatom.
+AB: A species of diatom.
+AC: A species of diatom.
+AD: A species of diatom.
+AE: A species of diatom.
+AF: A species of diatom.
+AG: A species of diatom.
+AH: A species of diatom.
+AI: A species of diatom.
+AJ: A species of diatom.
+AK: A species of diatom.
+AL: A species of diatom.
+AM: A species of diatom.
+AN: A species of diatom.
+AO: A species of diatom.
+AP: A species of diatom.
+AQ: A species of diatom.
+AR: A species of diatom.
+AS: A species of diatom.
+AT: A species of diatom.
+AU: A species of diatom.
+AV: A species of diatom.
+AW: A species of diatom.
+AX: A species of diatom.
+AY: A species of diatom.
+AZ: A species of diatom.
+BA: A species of diatom.
+BB: A species of diatom.
+BC: A species of diatom.
+BD: A species of diatom.
+BE: A species of diatom.
+BF: A species of diatom.
+BG: A species of diatom.
+BH: A species of diatom.
+BI: A species of diatom.
+BJ: A species of diatom.
+BK: A species of diatom.
+BL: A species of diatom.
+BM: A species of diatom.
+BN: A species of diatom.
+BO: A species of diatom.
+BP: A species of diatom.
+BQ: A species of diatom.
+BR: A species of diatom.
+BS: A species of diatom.
+BT: A species of di atom
+BU:
+BV:
+BW:
+BX:
+BY:
+BZ:
+CA:
+CB:
+CC:
+CD:
+CE:
+CF:
+CG:
+CH:
+CI:
+CJ:
+CK:
+CL:
+CM:
+CN:
+CO:
+CP:
+CQ:
+CR:
+CS:
+CT:
+CU:
+CV:
+CW:
+CX:
+CY:
+CZ:
+
+Fig. 17.—Various Diatomeae. *A* Synecha rufina. *B* Rhizotheca torula (from the two different sides). *C* Pinnularia sp. (from the upper side). Light several times on a portion of a plant, on the left a single one more highly magnified.
+
+32
+
+**Schizophyta**
+
+**Class 4. Schizophyta. Fission-Algae.**
+
+The individual cells are usually divided; the thallus consists in many of a single cell, in others of chains of cells, the cells dividing in only one definite direction (Figs. 18, 21). In certain Fission-Algae the cell-chain branches (Fig. 30) and a difference between the anterior and posterior ends of the chain is marked; in some, the cells may be united by a common wall, but in others the division takes place in two directions; and in others there are somewhat culi- nate masses, or rounded lumps of a less decided form, by the divisions taking place in three directions; or less defined masses may be formed by the lateral fission taking place at right angles.
+
+The cell-walls rarely become cellulose, they often swell considerably (Figs. 20, 22), and show distinct stratifications, or they are almost completely changed into a mucilaginous mass in which the protoplasts are suspended (Fig. 22). In some cases this condition is wanting. Vegetative reproduction by division and the separation of the divisional products by the splitting of the cell-wall or its becoming meconucleated; among the Nostocaceae, Lyngbyaceae, Synechococcales, Heterococcaceae, and other genera of Schizophytae, and others single reproductive akinetes are formed. Many Fission-Algae conclude the growing period by the formation of resting akinetes or aphanospores.
+
+The Schizophytae may be divided into two families:
+
+1. **Schizophyceae.**
+ *Family* Schizophyceae.
+ *Blue Green Algae.*
+
+All the Blue-green Algae are unicellular organisms, with means of a colouring material containing chlorophyll (chlorophyll I); but the chlorophyll in this substance is masked by a blue (phycoeyanin), or red (phycoerythrin, e.g. in Trichodesmium erythraeum in the Red Sea) colouring matter; this colouring matter is lost when the algae die and water after death. The colouring matter, in most of them, per- mutes the whole of the protoplasm (excepting the cell-nucleus), but in a few (e.g. Gloeocystis, Phycosphaera), slightly developed chromatophores are present. In some genera (e.g. *Chroococcus*, *Cyanidium*) filaments (cell-nucleus) a differentiation into apex and base (*Bacillariaceae*) may take place, and also between ordinary vegetative cells and heterocytes; these latter cannot divide, and are dis-
+ *Mylophycaceae*. Cyanophyceae.
+
+![]() A diagram showing the structure of a Schizophytae cell.
+
+SCHIZHEMEL 23
+
+tinguished from the ordinary vegetative cells (Fig. 22 b) by their larger size, yellow colour, and poverty of contents. Branching sometimes occurs and in either true or apuric.
+
+![]() A diagram showing the structure of a filament.
+**Fig. 16.** —Microcystis *syphogener*: a portion of a filament, the thick sheath enclosing only one cell-chain; in one place a cell is drawn out by the movement of the cell-chain is the other side of the filament, so that two filaments are formed, which are separated from each other.
+
+The cell-chain in the anterior branching divides into two parts, of which either one or both grow beyond the plane of division (Fig. 18) and often out to both sides (e.g. *Sympenema*), the divisions however, always take place transversely to the longitudinal direction of the cell-chain. In the true branching a cell elongates and then grows transverse to the cell-chain, and the division then takes place nearly at right angles to the former direction (*Simophyton*).
+
+![]() A diagram showing the structure of a resting alomite with heterocysts and new heterocysts forming.
+**Fig. 17.** —*Colletotrichum major*: a resting alomite with heterocysts; b d posteriorly arising from a resting alomite; c filaments with two heterocysts and the formation of new heterocysts; f part of a filament with a heterocyst, and mature resting alomites.
+
+Cilia are wanting, but the filaments are sometimes self-motile (or locomotive) and may be rapidly turned round their axes, partly slide forward or backward (*Oedogonium*).
+
+Reproduction takes place by spores and hormogonia in addition.
+
+24
+
+**SCHIZOPHYTA**
+
+to simple cell-division. Hormogonia are peculiar fragments of a cell-chain capable of motion, and often exhibit a vigorous motion in the sheath, until at last they escape and grow into a new individual (Fig. 18). The spores are reproductive akinetes (Chromatium), which are formed by the division of the vegetative cells enlarging and constructing a thick cell-wall (Fig. 19 c-f). On permination, this cell-wall bursts and the new cell-chain elongates in the same longitudinal direction as before (Fig. 19 b c). Many (e.g., Ochromonas) produce akinetes in their ordinary vegetative state. Aplanoplasmae are wanting.
+
+The Fission-Acini are very prevalent in fresh water and on damp soil, less so in salt water; they also occur in water which almost never freezes, but they are found in warm spring with a temperature as high as 50° C.
+
+The Family may be divided into 2 sub-families:
+
+1. **Heterocystes (heterocysts are wanting)**: *Chroococcaceae*, *Lymphodiscus*, *Lithothrix*.
+
+2. **Heterocystes (heterocysts present)**: *Nadecocaceae*, *Etimo-araceae*, *Septomonas* and *Sirreiphomycetes*.
+
+Order 1. **Chroococcaceae**. The individuals are—many-celled, but all the cells are uniform, usually spherical or platelike or globular masses, often surrounded by a mucilaginous cell-wall, but never forming cell-chains. Multiplication by division and symmetrical fission is rare, but reproductive akinetes are wanting.
+
+*Chroococcus*, *Aphanocapsa*, *Gloeococcus* (Fig. 20), *Calophyton*, *Merismopodium*, *Oscillaria*, *Candea*, *Coryne*, *Polygymnia*, *Gymnothorax*.
+
+Order 2. **Lyngbyaceae** (*Oscillariaceae*) (Fig. 21).
+
+The cells are discoid (Fig. 21), united to straight or slightly curved filaments, which are unbranched, or with sparsious branching. The ends of the cell-chains are similar, but the terminal one is distinct by asymmetrical resting akinetes being wanting. *Oscillaria* (Fig. 21), *Spirulina*, *Lyngbya*, *Microcoleus*, *Symphonie*, *Pleotoma*.
+
+25
+
+Order 3. *Chamaephonaceae.* The individuals are 1-
+nucleated, attached, unbranched filaments with differentiation into apex and base; without heterocysty. Multiplication by re-
+productive akinetes; resting akinetes are wanting. *Dermosporus,
+*Clastidium*, *Chamomiphon*, *Golovinella*, *Phragmoneumus*.
+Order 4. *Rivulariaceae.* The individuals are composed of mul-
+ticellular, unbranched filaments, without differentiation into apex and base; heterocysts present. Reproduction by synkinetes and resting akinetes.
+
+Some genera are not macrogynous, e.g. *Cylindropermann* (Fig.
+19). The cell-chains in others, e.g. *Nostoc*, wind in between one
+
+![]() A small illustration showing a plant-like structure with a central rod-like body and branches extending outward.
+Fig. 18.—*Nostoc* verrucosum. A. The plant in its natural size; b an irregularly folded
+hollow mass. B. One of the multicellular enlargements, with its heterocysts (A), embedded in
+its multinucleate sheath.
+
+another and are embedded in large structureless jelly-like masses,
+which may attain the size of a plum or even larger (Fig. 22); sometimes they are attached to other plants or to rocks by filaments attached to other bodies. Other genera as follows: *Aphaniz-
+monas* and *Anabaena* (in lakes and smaller pieces of water); *Nudobius* is partly pelagic. Some occur in the intercellular spaces of the leaves of *Equisetum*. These *Nostoc-forms* are found in *Anthoceros*,
+*Elionia*, *Sphagnion*, *Lemna*, in the roots of *Equisetum* and *Pteris*;
+*Anabaena* in Azolla.
+
+Order 5. *Rivulariaceae.* The individuals are multicellular
+filaments with differentiation into apex and base, and spurious
+branching and a heterocyst at the base of each filament. Re-
+production by synkinetes and resting akinetes, rarely by simple
+reproductive akinetes. *Rivularia*, *Glaucocystis*, *Incerta*, *Calothrix*.
+
+Order 6. *Secotytonaceae.* The individuals are composed of
+multicellular filaments with no longitudinal division; differenti-
+ation into apex and base very slight or altogether absent;
+
+Schizophysida
+
+26 BACTERIA.
+branching spores ; heterocysts present. Reproduction by ana-
+kinetes, rarely by resting akinetes and ordinary reproductive
+akinetes. Telosporia, Systenoma, Hassula, Microchaete.
+Order 7. Sirophoraceae. The individuals are formed of
+multicellular threads with longitudinal division ; true branching
+and Metachrona are wanting. Reproduction by apex and base.
+Reproduction by akinetes, rarely by resting akinetes
+and ordinary reproductive akinetes. Hapalosiphon, Stigomena,
+Cyanobrya, Nostotrichia, Multigloeus.
+
+Family 2. Bacteria.*
+
+The Bacteria (also known as Schizomyces, and Fission-Fungi) are the smallest known organisms, and form a parallel group to the Blue-green Algae, but separated from these Algae by the absence of their colouring material ; chlorophyll is perhaps found in a few cases in some of the Bacteria.
+
+The various forms under which the vegetative condition of the Bacteria appear, are termed as follows :
+1. Globular forms, coiçi (Figs. 27, 30 c): spherical or ellip-
+soidal, sometimes with a central nucleus loosely massed together and generally termed "Micrococcus".
+2. Rod-like forms : more or less elongated bodies ; the shorter forms have been styled "Bacterium" (in the narrower sense of the word), and the term " Bacillus" has been applied to longer forms
+of similar nature ; the longer forms are long, straight and cylindrical (Figs.
+28, 29, 30 E).
+3. Thread-like forms : unbranched, long, round filaments, resembling those of *Oscillatoria*, are pos-
+sible (very thin, non-grana-
+lar filaments : Fig. 30
+A, short small filaments)
+filaments, with strong, refractile grains or drops of sulphur (Fig.
+* The Bacteria are more usually included under Fungi. It seems better, how-
+ever, to place them under the Algae in a separate class with the Schizomyces.
+
+Fig. 25.-Spirillum sphaerulum. Four specimens. One has two cells at the same end, the sulphur granules are seen internally.
+
+BACTERIA. 27
+
+31; often self-motile). Branched filaments, with false branching like many *Sporangiophora*, are found in *Gladiolus* (Fig. 30 B, G).
+
+4. *Spiral forms*: Rod-like or filamentous bodies, which more or less strongly resemble a corkscrew with a spiral rising to the left. In general these are termed *Spirula* (Fig. 23); very attenuated forms are known under the name of *Vorticella* (Fig. 30 D). Of these, the elements are slender and flexible with a closely wound spiral (*Spirochaete* (Fig. 24).
+
+5. The *Mycetobacteria*, consisting of rounded cells arranged in one plane, generally in groups of four, and produced by divisions perpendicular to the plane.
+
+6. The *Saccharomyces*, consisting of roundish cells which are produced by cellular divi-
+sion, and all the three divisions of spores being into globular or ovoid masses ("parcels") e.g. *Saccharum* centriculii" (Figs. 28, 29).
+
+All Bacteria are unicellular. In the case of the micrococci this is self-evident, but in the "rod" "thread", and "spiral" Bacteria, very often numerous cells remain united together and their individual elements can only be recognised by the use of special reagents.
+
+![]() Fig. 31.—Bacillus centriculii. One surr.
+roundish cell, surrounded by a double contour,
+which are drawn with double contour are more
+distinctly than those cells lying deeper
+drawn with single contour.
+
+![]() Fig. 32.—Micrococcus minuta: a & d—successive stages of one individual (from a to d p.m.), f an individual of 2f cells.
+
+The common name "Zoogloea", which reminds us of *Nostoc*, is probably given by the cells being so closely packed that the number of individuals in active division are found embedded in a mass of mucilage, which either contains only one, or sometimes more, of
+
+28
+
+**EACTERIAL**
+
+the above-named forms. The individuals may eventually swarm out and continue their development in an isolated condition. Such mucilaginous masses occur especially upon moist vegetables (potatoes, etc.), on the surface of fluids with decaying raw or cooked meat, and on the surface of water. They form minute int-
+folds when the Bacteria, with their mucilaginous cell-walls, multiply so rapidly that there is no more room on the surface of the fluid.
+
+The cells of the Bacteria are constructed like other plant-cells in so far as their diminutive size has allowed us to observe them. The cell-wall only exceptionally shows the reactions of cellulose (in *Saccharum*, Lecanomus; also in a Vigna-bacterium, *Bacterium glycogenes*). The protoplasm is usually very thin. The body of the cell mostly appears to be an uniform or finely granu-
+lated protoplast. Very few species (e.g. *Bacillus viscosus*) contain chlorophyll; others are coloured red (purple sulphur Bacteria); the majority are colourless. The cell-walls are often impregnated with a starch-like material when treated with iodine before the spore-formation. Some Bacteria contain sulphur (see p. 37). The body, which has been described as a cell-sacculus, is still of a doubtful nature.
+
+Artificial colourings with aniline dyes (especially methyl-violet, gentian-violet, methylene-blue, fuchsin, Bismark-brown and Vesuvius) play an important part in the investigations of Bacteria.
+
+**MOVEMENT.** Many Bacteria are self-motile; the long filaments of *Lactobacillus* exhibit movements resembling those of *Oscillaria*. In many motile forms the presence of cilia or flagella has been proved by the use of special methods. In some cases only one or two cilia attached at one end both ends (Fig. 25) are distributed irregularly over the whole body; the cilia are apparently elongations of the mucilaginous covering and not, as in the other Algae of the proto-
+plasms. In Spirochaetae the movement is produced by the flexibility of the cell wall. Generally speaking, all motile forms have two kinds of swarm-cells (i.e. rotation round the long axis and movement in irregular paths); but either end has an equal power of proceeding forwards.
+
+The swimming motion must not be confused with the hopping motion of the very minute particles under the microscope (Brownian movement).
+
+**VEGETATIVE REPRODUCTION takes place by continued transverse**
+
+BACTERIUM.
+29
+
+division; hence the name "Fission-Fungi" or "Fission-Algae," has been applied to the Bacterium.
+
+Structure. The spores are probably developed in two ways. In the *exodophorus* species (Figs. 28, 29), the spore arises as a new cell inside the mother-cell. The spores are strongly refractile, and are much smaller than the mother-cell, and are similar to the aplanospores of other Algae. In addition to these there are the *arthrophorus* species in which the cells, just as in *Nototus* and other Blue-green Algae, assume the properties of spores without previously undergoing an endogenous new construction, and are shed by the parent cell in the course of vegetative generations (Fig. 27). The formation of spores very often commences when the vegetative development begins to be restricted.
+
+![]()
+A diagram showing the structure of a bacterium. The main body is divided into several smaller compartments, each containing a nucleus. The nucleus is surrounded by a cell wall. There are also smaller structures within the main body, possibly representing other cells or organelles.
+
+
+Fig. 27.—Leucobacter muscorum: a, a young, natural size; b, cross section of young cell with spores; c, mature spores; d, successive stages of germination.
+The spores are formed in the same way as in *Nototus*, but they may be seen on the external side of the mucilage covering. (See magnified fig.)
+
+
+The spores germinate in *Nototus* by the bursting of the external layer of the cell-wall, either by a transverse or longitudinal cleft, but always in the same way, in the same species (Fig. 28, example of transverse cleavage).
+
+Distribution. Bacteria and their germs capable of development, are found everywhere, in the air (dust), in surface water, and in the superficial layers of the soil. The number varies very much in accordance with the nature of the place, season, etc. They enter together with air and food, into healthy animals and occur always in their alimentary canal.
+
+29
+
+30 BACTERIA.
+
+Growth and reproduction depend upon the conditions of temperature. There is a certain minimum, optimum and maximum for each species; for instance (in degrees Centigrade)—
+
+![]()
+A diagram showing the stages of bacterial growth.
+
+
+For, bacteria, like all other cells of living, eucaryotic-celled, is a living, mobile, pair of rods ; a similar rod after the effects of the changes in temperature, and the presence of oxygen (aerobe formation); &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation; &c) an extensive stage of spore-formation;
+
+
+Fine, non-living globular,
+Minim. rods, partly cylindrical
+and without spaces, partly
+stretched out into long
+spires, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+spaces, with three longitudinal
+
+Eubacterium rubrum 4 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360 370 380 390 400 410 420 430 440 450 460 470 480 490 500
+
+Bacillus anthracis
+
+Spirillum cholerae assoiaton
+
+Bacterium tuberculoate
+
+The functions of life cease on a slight excess or minimum temperature. Numerous setting in when either these limits is passed. Crenotricha-throds provided with mucilaginous envelopes may, according to Zopf., sustain a tempera-
+ture at which the water would boil at once. The exposure to so low a temperature as --11° for a short time. It is not known at what degree cold the death the Bacteria oc-
+cur: the greatest degree heat which the vegetative cells can
+
+BACTERIlla
+
+31
+
+withstand is about the same as that for other vegetative plant-
+cells, namely, about 50-60°C. Certain Bacteria, e.g., E. thermo-
+philus, grow and thrive vigorously at 70°C. Many species, on the contrary, are able to bear far higher temperatures (in several species up to 80°C) but do not grow at 100°C; those of
+Bacillus subtilis, for instance, can withstand for hours tempera-
+ture of 100°C in nutrient solution; the spores remain capable of
+development after exposure to a dry heat of 122° C).
+
+The Bacteria are air, if preserved, killed many times when in
+the vegetative condition. The spores however, bear a much
+longer period of dryness, some even several years.
+
+OXYGEN. Some species cannot live without a supply of free
+oxygen. These include the Bacteria of the genus Bacillus, the
+Hansen-thalli, the Chorda-Micrococcus. Other species can thrive
+rigorously without supply of free oxygen, and are even checked in
+their development by the admission of air (Anaerobes), e.g., the
+bacteria of the genus Clostridium (Clostridium perfringens, Clostridium
+spoilator). A distinction may be drawn between obligate and
+faculative aerobes and obligate and facultative anaerobes.
+Several Bacteria, producing fermentation, may grow without the
+aid of oxygen when they are living in a solution in which they can
+only respire anaerobically. But these bacteria will not grow when
+an only supply of oxygen is available. A great number of the pathogenic Bacteria belong to the facultative anaerobes.
+
+A luminous Bacterium (Bacillus phosphoreus) which in the
+presence of a supply of oxygen gives a bluish-white light, has been found in sea-water. Phosphorescent Bacteria have fre-
+quently been observed upon decaying fish-sea, as well as on the
+feet of fish. They are also found in fermented meat from cold fish
+to beef, etc., the latter may be made luminous.
+
+Organic carbon compounds are indispensable for all Bacteria,
+(except, as it appears, for the nitifying organisms), so that they can
+only live in solutions containing organic matter or its derivatives. The
+supplies of nitrogen, which also they cannot do without, can be ob-
+tained equally well from organic compounds as from inorganic
+salts, such as salt-potato or ammonia-combustibles. The various "ab-
+sorption" processes are therefore very similar.
+
+While Moulds and Yeast-Fungi grow best in an acid substratum,
+the Bacteria, on the other hand, generally thrive best in a neutral or slightly alkaline one.
+
+32
+
+**BACTERIA**
+
+In *sterilization*, *disinfection*, and *antiseptic*, means are employed by which the Bacteria are killed, or checked in their development, for instance, by heat (ignition, cooking, hot vapours, hot air, etc.), or poisons (acids, corrosive sublimate). The process of preserv-
+ing articles from the action of Bacteria is called *sterilization*; it is essentially sealed, aims at destroying the Bacteria, or the spores of those which already may be present in them, and excluding all others.
+
+As the Bacteria are unable to assimilate carbon from the car-
+bonic acid of the air, but must obtain it from the carbon-com-
+pounds already in existence in the organic world, they are either
+*asphyxieous* or *parasites*. Some are exclusively either the one or the other. Others are intermediate between these two forms,
+transitional forms among them, some of which are at ordinary
+times asphyxieous, but may, when occasion offers, complete their
+development wholly or partly as parasites—facultative parasites: others are parasitic only during a certain stage of their
+development as asphyxieous—facultative asphyxieous.
+
+All chlorophyll-free organisms act in a transforming and dis-
+turbing manner on the organic compounds from which they obtain
+their nourishment. In this way they produce, each after its kind, compounds of a less degree of
+complexity, i.e. they produce fermentation, putrefaction, sometimes
+the formation of poisons, and in living beings often disease.
+
+Those organisms which contain chlorophyll are called *photosynthetic*;
+this word, however, is also employed for similar transformations in purely chemical materials (inorganic ferments or enzymes).
+
+Many organic ("living") ferments, among which are Yeast-
+cells and Bacteria, can be decomposed into certain
+inorganic and soluble ferments (enzymes) which may produce
+other transformations without themselves being changed. Dif-
+ferent organisms may produce in the same substratum different kinds of transformation. For example, the same substance may be produced by different species of Fungi; but in different pro-
+portions, and the same species produces in different substrata,
+different transformations (e.g. the Vinegar-bacteria oxidize diluted alcohol to vinegar, and eventually to carbonic acid and water).
+
+In the study of Bacteria it is absolutely necessary to sterilize the vessels employed. This is done by boiling with steam for 10 minutes; then from Bacteria germi and also to preserve the culture from the intrusion of any
+foreign germs ("pure-cultures"). A firm, transparent, nutritive medium is
+
+BACTERIA.
+33
+
+frequently employed. This may be prepared by adding to the nutrient solu-
+tions (broth) either gelatin or, when the Bacteria are to be cultivated at
+blood-heat—serum of sheep's or calf's blood, agar-agar or carrageen; serum
+of human blood, or any other suitable material. The "nutrient solu-
+tures" are frequently employed, Le. the germs are isolated by shaking them
+with the method liquid nutrient solution, which is then spread on a glass plate
+and allowed to dry. When the plates are examined after 24 hours, large
+colonies, these remain separate in the solid substratum and it is easy to puruse
+further development. Similar plate cultures may also be cultivated in
+the same manner with the addition of a little yeast extract. These can be
+placed in "moist chambers" free from Bacteria. By noting a few cells (if pos-
+sible) by means of a fine platinum wire, pure cultures for further investi-
+gation may be obtained.
+
+In order to prove the relationship between pathogenic Bacteria and certain
+classes of the experimental protozoa, it is necessary to know how the inoculation
+of Bacteria into cultures leads into healthy animals, it is very impor-
+tant to know this.
+
+It has not so far been possible to establish a classification of the Bacteria,
+as the life-history of many species has not yet been sufficiently investigated. The opinions of botanists are at
+variance with each other with regard to the forms of growth of a
+particular kind. Some species are pleomorphic (many-formed)
+while others possess only one form.
+
+The following Bacteria are Saprophytes:
+
+Colonial forms, such as those of water and running water which is impregnated with organic matter; the cell-chains have false branching. According to Zopf, Leciderea oxylus is one of
+the forms of this substance, in which, containing ferrous iron
+(eg. as FeCO₃), regularly embeds ferrous iron in its sheath by means of
+Leciderea oxylus. According to Zopf, the other iron-bacteria, according to Wimogersky (1888), do not continue their growth in water free from protoxide of iron; while they multiply enormously in water which contains this salt of iron.
+The forms of development of Chondrocladium dichotomum, lags,
+and lakes, are probably due to the activity of the Iron-bacteria.
+These forms which, according to Zopf's views, represent the
+forms of development of Chondrocladium dichotomum are placed together in fig. 105. In this figure a group of cells is shown at 10 times magnified, attached to a Vachneria. The largest one is branched like a tree, with branches of ordinary form; a specimen with
+spirally twisted branches is seen to the right of the figure; at
+the left hand side is seen Leciderea oxylus-like form. D shows the
+
+On the classification of Bacteria see "System der Bakterien," by Dr.
+W. Mignola. Jena, 1897.
+
+W. B.
+D
+
+34
+
+BACTERIA.
+
+manner of branching and an incipient Coccos-formation. C a Coccos-mass whose exit from the sheath has been observed. D the
+
+![]()
+A: A cluster of short rods.
+B: A cluster of long, thin rods.
+C: A cluster of short, thick rods.
+D: A cluster of long, thin rods.
+E: A cluster of short, thick rods.
+F: A cluster of short, thick rods.
+G: A cluster of short, thick rods.
+H: A cluster of short, thick rods.
+I: A cluster of short, thick rods.
+J: A cluster of short, thick rods.
+K: A cluster of short, thick rods.
+L: A cluster of short, thick rods.
+M: A cluster of short, thick rods.
+N: A cluster of short, thick rods.
+O: A cluster of short, thick rods.
+P: A cluster of short, thick rods.
+Q: A cluster of short, thick rods.
+R: A cluster of short, thick rods.
+S: A cluster of short, thick rods.
+T: A cluster of short, thick rods.
+U: A cluster of short, thick rods.
+V: A cluster of short, thick rods.
+W: A cluster of short, thick rods.
+X: A cluster of short, thick rods.
+Y: A cluster of short, thick rods.
+Z: A cluster of short, thick rods.
+AA: A cluster of short, thick rods.
+AB: A cluster of short, thick rods.
+AC: A cluster of short, thick rods.
+AD: A cluster of short, thick rods.
+AE: A cluster of short, thick rods.
+AF: A cluster of short, thick rods.
+AG: A cluster of short, thick rods.
+AH: A cluster of short, thick rods.
+AI: A cluster of short, thick rods.
+AJ: A cluster of short, thick rods.
+AK: A cluster of short, thick rods.
+AL: A cluster of short, thick rods.
+AM: A cluster of short, thick rods.
+AN: A cluster of short, thick rods.
+AO: A cluster of short, thick rods.
+AP: A cluster of short, thick rods.
+AQ: A cluster of short, thick rods.
+AR: A cluster of short, thick rods.
+AS: A cluster of short, thick rods.
+AT: A cluster of short, thick rods.
+AU: A cluster of short, thick rods.
+AV: A cluster of short, thick rods.
+AW: A cluster of short, thick rods.
+AX: A cluster of short, thick rods.
+AY: A cluster of short, thick rods.
+AZ: A cluster of short, thick rods.
+BA: A cluster of short, thick rods.
+BB: A cluster of short, thick rods.
+BC: A cluster of short, thick rods.
+BD: A cluster of short, thick rods.
+BE: A cluster of short, thick rods.
+BF: A cluster of short, thick rods.
+BG: A cluster of short, thick rods.
+BH: A cluster of short, thick rods.
+BI: A cluster of short, thick rods.
+BJ: A cluster of short, thick rods.
+BK: A cluster of short, thick rods.
+BL: A cluster of short, thick rods.
+BM: A cluster of short, thick rods.
+BN: A cluster of short, thick rods.
+BO: A cluster of short, thick rods.
+BP: A cluster of short, thick rods.
+
+SACCHARILL 35
+
+and after treatment with picro acid, which causes the chain-like structure to become apparent. G. A portion of a plant with con-
+spicuous sheath, two lateral branches are forming before. H. Part of a plant, whose cells have divided and form Cocci. The original
+form of the cells in which the Cocci are embedded may still be recognized in the sheath, but they are now enclosed in a con-
+spicuous sheath, from which a series of rods is about to emerge; the rod
+near the bottom is dead, and has remained lying in the sheath. K part of a plant which is forming Cocci, those at the top are in
+the zoogloea-stage, at the base they are elongating to form rods
+and Cocci. L. A portion of a plant with several short spirochaetes,
+which divide into motile Bacillus-forms; the ruyas at the free
+ends indicate the currents which the filaments produce in the water.
+M. A spirally-twisted, warming filament, before and after division
+of its nucleus. N. A portion of a plant with several short
+rods—all of these spirilla, zoogloea, etc., which Zepte has con-
+sidered with Ciala diathecia, are according to Winiagrodsky, inde-
+pendent organisms.
+
+Micrococcus acidophilus produces arinal fermentation (transformation of arinal matter into ammoniacal carbonate); sericin; round cells
+which unite to form bent chains or a zoogloea.—Several other
+kinds of Bacteria have the same action as this one: in damp
+soil, on the surface of milk, and on articles of food, acids are pro-
+duced by M. nitricusf and several different kinds of Bacteria.
+
+Micrococcus prodigiosus is found on articles of food containing
+starch; "bleeding bread" is caused by this bacterium, which has the power of producing a red pigment; it also occurs in milk, and produces lactic acid.
+
+Lemonosotus mesentericus is the frog-spawn Bacterium (Fig. 27)
+which is found in sugar manufactories, and has the power of
+producing acids from sugar. In some of the solutions which have been derived from plants, e.g. in beetroot-solutions in manu-
+factories, where large accumulations of musilage are formed at the expense of the sugar, with an evolution of carbonic acid. The
+cells are long and thin, and contain many vacuoles; they form thick
+musilingae-cell walls, and form white "Nostoc"-clumps. The
+musilage eventually deliquesces and the cells separate from each other;
+anthorophores—Similar viscous deteriorations occur in
+beetroot-wine—may then be drawn out into long, string-
+like filaments—ruptures
+
+Bacterium aceti, the Vinegar-bacterium, oxidizes alcohol into
+
+36 BACTERIA
+
+acetic acid (acetum-fermentation) and forms a greyish covering of Bacteria (= Vinegar-mother,) on the surface of the liquid; the acetic acid formed, becomes by continued oxidation by E. acet., again transformed into carbonic acid and water. Aerobic; short cylindrical cells, often united into chains, or to form a zoogloea-like mass, or sometimes into long rods, or long bacilli, or other kinds with ball- or rod-forms sometimes become swollen, spinelike-shape, or oval links; they are supposed to be diseased forms? ("Inversion-forms").
+
+Bacillus subtilis (Bacillus lactici, Zopf.) is always found in milk which has stood some time for, and in sour foods (cabbage, cucumbers, etc.); it turns the milk sour by producing lactic acid fermentation in the sugar contained in the milk; the lactic acid formed, is very similar to that produced by Lactobacillus. It resembles the Vinegar-bacteria, occurring as small cylindrical cells, rarely in short rows; not self-motile—Several other Bacteria appear to act in the same way, some occurring in the mouth of animals being; but these are not so numerous as those of the lactic flora.
+
+The kefir-grains which are added to milk for the preparation of kefir, contain in large numbers a Bacterium (Diplococcus casei) in the zoogloea-form, a Yeast-form, and Racibora lactica. Kefir is a somewhat similar beverage manufactured by the inhabitants of the Caucasus, from the milk of cows, goats, or sheep, and is sometimes used as a medicine. In the production of kefir, lactic acid fermentation takes place first; this is followed by alcoholic fermentation; the alcoholic fermentation in another part, and the casein which had become curdled is partially liquefied (peptised) by an enzyme of a Zoogloea-bacterium.
+
+Racibora lactica (Racibora bursa), the Butyric acid-bacterium (Fig. 29), is a very common anaerobe which produces fermentation in sugar and lactic-acid salts, and whose principal product is lactic acid. It destroys articles of food and (together with other bacteria) causes putrefaction; its action is essential which is necessary in the making of cheese; it is very active wherever portions of plants are decaying, destroying the cellu-
+lose in the cell-walls of herbaceous plants, and is thus useful in the preparation of manure. It is usually short cylindrical, sometimes united into short rows; endo-
+3 According to Hansen these are not disease forms, but occur regularly under certain conditions, e.g. temperature.
+
+**BACTERIA**
+
+37
+
+sporons; the spore-forming cells oval, assume very different forms, and show granulose reaction. The germ-tube grows out in the direction of the long axis of the spore.
+
+*Bacillus subtilis*, the Hay-bacillus, is developed in all decoccions of hay; a very similar species, *Bacillus ferricillinus*, endosporous (xiphosporous) the spore-wall ruptures transversely on germination.
+
+*Crenothrix kühniana* occurs in the springs of many baths, in water, in wells or draining-pits.
+
+*Fungi* are found in the water of the Blue-green Alga *Oscillatoria*. Long filaments formed of cylindrical cells which are attached by one of the ends, but which are nearly always free when observed. The filaments, like those of *Oscillatoria*, describe conical figures in their course, and are often seen to be divided into two branches, one another; sometimes they are wanting; strongly refractive sulphur bulbs are found in the interior. The Beggiatrae are the most prominent of these organisms; they occur very commonly in large numbers, wherever plant or animal remains are de-
+caying in water in which sulphurised hydrogen is present; thus for example, *B. alfa* (Fig. 51) is frequently as a white covering or almy film on mud containing organic remains. *B. microlis* is remarkable for its size and its strong peristalsis movements. It is a very active organism, the sulphured hydrogen, and accumu-
+late sulphur in the shape of small grains of soft sulphuretted sulphur, which in the living state are dissolved in the crystalline state. They next oxidise this sulphur into sulphuric acid, which is immediately rendered neutral by ab-
+sorption of oxygen from the air,
+off in the form of a sulphate, thus CaSO₄ is principally changed to CaSO₃. In the absence of sulphur the nutritive processes are suspended, and consequently death occurs either sooner or later. The fluid which only contains traces of organic matter, in which organisms devoid of chlorophyll are not able to exist. The Beggiatrae very frequently form white, bulky masses in sulphur wells and
+
+![]() Beggiatrae alba: a filament of a blue-green alga.
+Pan. 81. - Beggiatrae alba: a filament of a blue-green alga.
+The alga is covered with a film of sulphured hydrogen; after some time a con-
+siderable amount of sulphured hydrogen has been absorbed; it takes an additional four hours to assimilate this substance; then the alga becomes cyano-
+genous, by this means the trans-
+portation of oxygen to the vacuoles have become visible.
+
+38
+BACTERIA.
+
+in salt water, the traces of organic material which the sulphur water contains proving sufficient for them. The cellulose-fermenta-
+tion, to which the sulphur wells are mainly susceptible owe their origin, mainly proceed by the reduction of the organic matter, formed during the cellulose fermentation by the reduction of CaSO₄ is calcium carbonate, and CO₂ by the action of oxygen (Helmholtz, 1871).—Other Sulphur-bacteria, e.g., the purple Sulphur-bacteria, r. e. R. aerogenes, Spirillum sanguineum (Fig. 25), Bacillus sputorum, etc., have their own special mode of nutrition. In these bacteria, which like chlorophyll, has the power, in the presence of light, of giving off oxygen (as proven by T. W. Eigendam, 1888; an oxygen-consuming Bacterium). These three kinds of bacteria are found in water according to Wundtberg, not photomembrane cells but embrace numerous species.
+
+Many Spirilla (Spirillum tenuis, S. undulata, S. plicillate, and others) are found in decaying liquids.
+
+Bacteria (especially Bacilli) are the cause of many substances emitting a putrid smell and of various changes in milk.
+
+Parasitic Bacteria are also found in human beings; but the relation between 'host' and parasite may vary in considerable degree. Some parasites do no injury to their host, others produce dangerous contagious diseases; some choose only a special kind as host, while others attack all kinds of hosts indiscriminately. There are further specific and individual differences with regard to the propagation of the host, and every individual has not the same receptivity at all times.
+
+The number of human BACTERIA. Several of the above mentioned asphyxieties may also occur in the alimentary canal of human beings; e.g., the Hay-faeculae, the Butyrice-acidifica-
+tion, etc., but the gastric juice prevents the development of others, at least even those which are harmful. The "bacillus cere-
+trical," packet-bacterium," is only known to occur in the stomach and intestines of human beings, and makes its appearance in cer-
+tain diseases of the stomach (dilatation of the stomach, etc.) in great numbers; it is also found in certain cases of enteric fever. It occurs in somewhat cubical masses of roundish cells (Fig. 25).
+
+Lethal dangerous parasites. In the mouth, especially between and on the teeth, a great many Bacteria are to be found (more than fifty different species have been described); they are chiefly very thin filaments which are united into bundles). Micrococcii in large lumps, Spirochete colána, etc. Some of them are known to be injurious, as they contribute in various ways to the decay of the teeth (necrosis dentium); a Micrococcus, for instance, forms bacterioidal
+
+EUTHERIA.
+
+in materials containing sugar and starch, and the acid dissolves the lime salts in the external layers of the teeth; those parts of the tooth thus deprived of lime are attacked by other Bacteria, and become dissolved. Inflammation in the tissues at the root of a tooth, is usually produced by septic materials which have been formed by Bacteria.
+
+DANGEROUS PARASITES. In a large number of the infectious diseases of human beings and animals, it has been possible to prove that parasitic bacteria are the cause of the disease. Various pathogenic bacteria of this nature, belonging to the Cocci, Rods, and Spinal Bacteria, groups are mentioned in the following:
+
+Pathogenic Micrococci. *Staphylococcus pyogenes aureus* produces a disease of various names, but with a severe presence in (internal organs). Some effects are produced by:
+*Streptococcus pyogenes*, which is the most frequent cause of malignant purulent fever; it is perhaps identical with—
+*Streptococcus haemolyticus*, which is the cause of erysipelas in human beings.
+*Diplococcus pneumoniae (A. Fränkel) is the cause of pneumonia, and of the epidemic cerebro-spinal meningitis.*
+*Gonococcus (Neisser) is the cause of gonorrhoea and inflammation of the urethra.*
+
+Pathogenic Rod-Bacteria. *Bacillus cholerae gallinarum*, an aerobic, facultative parasite which produces fowl-cholera among poultry; it is easily cultivated on various substrates as a sapro- phyte, and may also be transmitted through wounds and by food, and may also be communicated to mammals.
+*Bacillus anthracis*, the *Bacillus* chalarae (Fig. 32), chiefly attacks mammals, especially herbivorous animals (house mice, guinea-pigs, rabbits, etc.), but also birds (chickens, pigeons, etc.) (including human beings), and in a still less degree the Carnivores. Aerobic. Cylindrical cells, 3-4 times as long as broad, united into long rod-like bodies, which may elongate into long, bent, and somewhat twisted rods. The mode of transmission takes place without the throwing off of any spore-membrane (compare Hay-bacillius p. 37 which resembles it). Contagion may take place both by introduction into wounds, and from the mucous membranes by inhalation or contact with infected material, and by spores; in intestinal anthrax, however, only by spores. The Bacillus multiplicates as soon as it has entered the blood, and the anthrax disease commences. The Bacilli not only give off poison,
+
+![]() A diagram showing different types of bacteria.
+
+40
+
+**SACCHARIA**
+
+but also deprive the blood of its oxygen. Vegetative cells only occur in living animals. This species is a *faculative parasite* which in the first stage is a saprophyte, and only in this condition forms spores.
+
+*Barilla barillenae* produces tuberculosis in human beings, also in domestic animals (pernicious). It is a distinct parasite, but may also live saprophytically. It is rod-formed, often slightly bent, and is recognized principally by its action with dinitro- (when stained with an alkaline solution of methyl-blue or carbol-fuchs).
+
+![]() A diagram showing the structure of Bacillus barillenae.
+Fig. 32.—*Bacillus barillenae*. The formation of the spores, magnified hundreds of times.
+
+sin, it retains the colour for a long time even in solutions of mineral acids, in contrast with the majority of well-known Bacteria); it probably forms spores which are able to resist heat, dryness, etc.
+
+*Bacillus luteus* produces leprosy; *Bacillus maltese* produces glanders; *Bacillus tetani*, *bacillus anthracis*, *bacillus cereus*, *bacillus subtilis*, *bacillus diphtheriae*, *diphtheria*; *bacillus typhoides*, typhoid fever, etc.
+
+**Pathogenic Spiral Bacteria.** *Spirochete obramovi* (Fig. 24) produces intermittent fever (febris recurrenta); it makes its appearance in the blood during the attacks of fever, but it is not to be found during intervals when there is no fever. Obligate parasite.
+
+*Spirillum cholerai asiaticum* (Microspira comma) without doubt produces Asiatic cholera; an exceedingly motile spirillum, which is also found in short, bent rods (known as the "Comma-bacillus"),
+
+**EACTERIA.**
+
+It lives in the intestines of those attacked by the disease, and gives off a strong poison which enters the body. It is easily cultivated as a saprophyte.
+
+A great many circumstances seem to show that a number of other infections diseases (syphilis, small-pox, scarlet-fever, measles, yellow fever, etc.) are caused by Bacteria, but this has not been proved with certainty in all cases.
+
+It has been possible by means of special cultivations (ample supply of oxygen, high temperature, antiseptic materials) to produce varieties of Bacteria which differ from each other (e.g., *Bacillus coli* and the anthrax *Bacteria*) physiologically varieties which are distinct from those appearing in nature and possess a less degree of "virulence", i.e. produce fever and less dangerous symptoms in the animal host. The importance of such physiological varieties can come to be of great practical importance from the fact that they are used as vaccines, i.e. these harmless species produce in the animals inoculated with them immunity from the pathogenic infection. Because of this, which they have acquired, they are no longer affected by the change of the products of one or more of the Bacteria, but we do not yet know anything about the way in which they act on the animal
+
+![]()
+A diagram showing two blood-cells labeled "a" and "b". The text below reads: "Fig. 38.--a and b. The same blood-cell of a Frog, a in the act of engulfing an antirrheumatic Bacterium, b in the act of engulfing a few minutes when the bacterium has been shortened."
+
+
+The white blood corpuscles, according to the Metchnikoff, play the part of "Phagocytes" by absorbing and destroying the less virulent Bacteria which have entered the organism.
+
+40n.
+BACTERIA.
+
+blood, and by so doing they are gradually enabled to overcome those of a more virulent nature.
+
+**BACTERIA PATHOGENIC TO PLANTS.** Recent investigations have thoroughly proved the parasitization of Bacteria upon plants—trees, grasses, etc., but whether these plants have undoubtedly been immune to these organisms, though their behaviour as vegetable parasites in other cases has not been strictly defined. The following examples may be quoted:
+
+![]() A cell from Turnip attacked by *Pseudomonas destructans*. The bacteria are seen in the cell-walls, along with the track of the middle lamella. The cell-wall is much thinner than that of the surrounding leaf-sheets along the middle lamella, in which the destruction is more strongly marked. B. *P. destructans* with single polar flagellum.
+
+*Pseudomonas destructans* causes the White Rot of the Turnip (Brassica napus). The action of this Bacterium upon the cells of its host is similar to that of certain parasitic Fungi; it produces a toxin which dissolves the middle lamella of the plant-cells, a process which has the power of dissolving the middle lamella, and causing the softening and swelling of the cell-wall. By this means the Bacteria rapidly invade the tissues of the host, burrowing through the cell-walls and extending into the cell-contents and intercellular spaces (Fig. 38a); the collapse occurs with the death of the cells,
+
+A
+
+b
+
+B
+
+CONJUGATE. 41
+
+and the root is reduced to a mere watery pulp. This organism generally infests the plant through a wound, but it is able to enter the epidermis of undeveloped leaves.
+
+*Pseudomonas campestris* produces a brown discolouration of the vascular tissues in the roots and leaves of Cruciferaeous plants. It attacks the woody portion of the vascular bundles, and is found in great numbers blocking up the wood-vessels. The infection of the leaves may take place through the water-pores, and spread thence along the vascular bundles to other parts of the plant.
+
+*Pseudomonas hyacinthi* is pathogenic to Hyacinths, spreading especially through the vascular system. Yellow spots are found on the bulbs and foliage which are due to the lesions becoming filled with a yellowish pus produced by this organism.
+
+*Bacillus subtilis* attacks the Tomato, Egg-plant, and Potato, causing the withering and final death of the young shoots.
+
+*Bacillus betoi* gives rise to the "Gummosis" of the Sugar Beet.
+
+*Microccus tritici* is an organism which infects the grain of Wheat, and preys upon the proteins and starch, forming what is known as "Pink Wheat."
+
+*Bacillus malii*, it has lately been shown, is the cause of the blisters so common on the Apple and Pear. This parasite is probably carried by Aphidids, and affects an entrance through the wounds caused by these insects.
+
+Class 5. Conjugate.
+
+The Algae belonging to this class have chlorophyll, and pyrenoid round which starch is formed. The cells divide only in one direction, they live solitarily, or united to form filaments which generally float freely (solids attached). Swarm-cells are wanting.
+The fertilization is ingamorous (conjugation) and takes place by means of zoospores. The zygote, after a period of rest, produces, immediately on germination, one or more new vegetative
+
+42
+
+CONJUGATE.
+
+individuals; sometimes akinetes or splanosporae are formed in addition. They only occur in fresh or slightly brackish water.
+Order 1. Desmidaceae. The cells generally present markings on the outer wall, and are mostly divided into two symmetrical halves by a transverse wall, which, however, there is no symmetrical division of the protoplasmic cell-contents. The cell-wall consists nearly always of two layers, the one overlapping the other (Fig. 35 C). The cells either live solitary or are united into innumerable filaments. The formation of protospores, formed by the fusion of the two conjugating cells, is a symmetrical division; on germination produces one (or after division 2, 4 or 8) new vegetative individual. The chromatophores are either star-, plate-, or band-shaped, and regularly arranged round the long axis of the cell.
+
+Fig. 36.—A cell of *Dyssimnium brevistem*, external view showing the distinction of the pores. A A portion of the same cell, showing the pores with surrounding protoplasmic projections. C Cut surface of *Euplectra* *wanseri* during cell-divisions ; the external pores being closed by a transverse wall. D A portion of a cell of *Desmidium* *pulchrum*.
+
+The Desmidaceae are not able to swim independently; many species, however, show movements of different kinds by rising and sliding forward on the substratum. Those movements, which are partly dependent upon, and partly independent of light and the force of gravitation, are connected with the protrusion of a mesoglea-projection. This mesoglea, which is produced by the whole individual, may acquire a prismatic structure, it is secreted by the protoplasmic threads which project through certain pores definitely situated in the walls (Fig. 35 A–D).
+
+Narrazione is a genus belonging to this order by division. A good example of this is found in *Cosmarium botrya* (Fig. 36 A–D). The nucleus and chromatophores divide, and simultaneously the central indentation becomes deeper, the outer wall is then ruptured making a short, circular canal between the two halves to which it is attached (Fig. 36 C). After elongation the canal is divided by a central transverse wall, which commences as a ring round its
+
+CONJUGATE.
+43
+
+inner surface and gradually forms a complete septum. The dividing wall gradually splits, and the two individuals separate from each other, each having one an old and a new half. The two
+
+![]() A, B, C, D
+Fig. 36.—Coniariaceae botryoides. A-D Different stages of cell-divisio.
+
+daughter-cells bulge out, receive a supply of contents from the parent-cell, and gradually attain their mature size and development (Fig. 36 f-f-D). Exceptions to this occur in some forms.
+
+In the Coniariaceae, the cells are often so large that where the two conjugating cells unite by a short tube (conjugation-canals), which is not developed at any particular point. The plasmodiocytes merge together after the dissolution of the dividing wall, like two drops of water, almost without any trace of preceding construction, except that the whole of the outer layer of the cell is in contact with the conjugating cells. The conjugating cells in the others lie either transversely (e.g. Cosmarium, Fig. 37 d ; Staurastrum, etc.), or parallel to one another (e.g. Pentium, Closterium, etc.), and
+
+![]() Fig. 37.—Coniariaceae monosporic. a-c same individual seen from the side, from the end, and from the edge; d-f stages of conjugation; p-d germination of the zygote.
+Fig. 37.—Coniariaceae monosporic. a-c same individual seen from the side, from the end, and from the edge; d-f stages of conjugation; p-d germination of the zygote.
+
+emit a short conjugation-canal (Fig. 37 d) from the centre of that side of each cell which is turned towards the other one. These canals touch, become spherical, and on the absorption of the divided contents they form a long conjugation-canal (Fig. 37 e), which is often surrounded by a mucilaginous envelope. The zygote, which is often spherical, is surrounded by a thick cell-wall, consisting of three layers; the outermost of these
+
+44
+
+CONJUGATE
+
+sometimes bears thorn-like projections, which in some species are simple (Fig. 37 f), in others branched or variably marked ; in some, however, it remains always smooth (e.g. *Tetramorus*, *Desmidium*). Deviation from this mode of conjugation may occur within one species, e.g. *Desmidium* *cylindricum*. In the formation of the contents of the zygote emerge, surrounded by the innermost layers of the wall (Fig. 37 g, h), and generally divide into two parts which develop into two new individuals, placed transversely to each other (Fig. 37 i); these may have a somewhat more simple marking than is generally possessed by the species.
+
+![]() A B C D E F G H I
+Fig. 38.—*Desmidium*. A *Glotterus* *quadriform*; B *Fusius* *crassicaulis*; C *Muscus* *crassus* (front and side view); D *Rudisius* *dolosus*; E *Streptocarpus* *medullaris* (cut view).
+
+The most frequent genera are—
+
+A. Solitary cells : *Mesophyllum*, *Pezium* (Fig. 38 E), *Ctenobryon*, *Echinodorus*, *Heterostoma*, *Lemna*, *Lemnoides*, *Lemnochara*, *Lemnochara* (Fig. 38 f, g), *Xanthidium*, *Streptocarpus* (Fig. 38 E), *Platymenium*, *Dichotomum*, *Pterocarpon*, B. Cells in pairs : *Zygnema*, *Zygnemopsis*, *Zygnematale*, *Zygnematales*, *Gymnostoma*, *Anclodiscus*, *Gymnosporus*.
+
+Order 2. Zygnemacaea. Cell-wall without markings. The cells are cylindrical, not constricted in the centre, and (generally) united into simple, unbranched filaments. The whole contents of the conjugating cells take part in the formation of the zygote, which on division gives rise to two new individuals.
+
+*Spirogyra* is easily recognised by its spiral chlorophyll band ; Zygnema has two star-like chromatophores in each cell (Fig. 40); both these genera are very common Algae in ponds and ditches.
+
+CONJUGATE.
+45
+
+The conjugation among the Zygnemaceae takes place in the following manner: the cells of two filaments, lying side by side, or
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+A
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+B
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+C
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+D
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+E
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+F
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+G
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+H
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+I
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+J
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+K
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+L
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+M
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+N
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+O
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+P
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+Q
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+R
+
+![]() A diagram showing the process of conjugation in Zygnemataceae. The two cells, one being situated above the other in the same filament (Fig. 41), push out small protuberances opposite each other (Fig. 39, a, b, c); these finally meet, and the dividing wall is absorbed so that a tube is formed connecting one cell with the other.
+S
+
+![]() A diagram showing three stages of conjugation between two zoospores of Spirogyra vulgaris: In stage Ia both zoospores are still alive; they glide through their respective confluences until they come into contact at some point on their periphery; then they round off to form an intercellular space which becomes filled up by cytoplasmic contents; this space remains open during all subsequent stages; when both zoospores have rounded off they become connected by means of an intercellular bridge which grows from their peripheries towards their center; this bridge grows until it fills up completely both spaces between them; then both zoospores round off again to form new zoospores which are now free from their parent body; this stage corresponds to stage Ib; stage II shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage IIb; stage III shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage IIIb; stage IV shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage IVb; stage V shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage Vb; stage VI shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage VIb; stage VII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage VIIb; stage VIII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage VIIIb; stage IX shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage IXb; stage X shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage Xb; stage XI shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XIb; stage XII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XIIb; stage XIII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XIIIb; stage XIV shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XIVb; stage XV shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XVb; stage XVI shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XVIb; stage XVII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XVIIb; stage XVIII shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XVIIIb; stage XIX shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XIXb; stage XX shows how both zoospores have rounded off again to form new zoospores which are now free from their parent body; this stage corresponds to stage XXb;
+
+**CONJUGATE**
+
+At first glance it may appear as though conjugation occurs only between two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arranged filaments.
+
+**Zygnema** *sp.* has been observed by me undergoing conjugation under conditions similar to those described for *Spirogyra* *vulgaris*. It was found that after having passed through several stages of division and growth it became possible for two filaments lying side by side or parallelly arrangedfilament
+
+46
+
+**Chlorophyceae.**
+
+may be found between the cells in the two filaments, those in the one whose protoplasmic contents pass over being cylindrical, while those of the recipient one are more barrel-shaped, and of a larger diameter. The former may be regarded as a male, the latter as a female plant. The zygote germinates after a period of rest, and grows up to form a new plant.
+
+Order 3. **Mesocarpaceae.** The cell-walls are globular, uncon-
+stricted in the centre, and united into simple unbranched filaments.
+The chromatophore consists of an axial chlorophyll-plate, with several smaller ones on each side, and containing a nucleus of two cells (Fig. 45) (sometimes three or four), but the whole pro-
+toplasmic contents of the cells do not take part in this process, a
+portion always remaining behind; the anlagenomes coalesce in
+the conjugation-cell. The zygote then forms appears incapable
+of germination until after 2-3 divisions. Of the cells so formed,
+
+![]() Fig. 45.—Mesocarpaceae. Cells showing various modes of conjugation; at $a$ tris-
+mion ; $b$ quadruplication ; $c$ quadruplication of the zygote.
+
+**Class 6. Chlorophyceae (Green Algae).**
+
+Those Algae are coloured green by chlorophyll, seldom in com-
+bination with other colouring matter, and then especially with red.
+The product of sexual reproduction is a zygote which generally
+accumulates round certain specially formed portions of protoplasm
+termed pyrenoids. The thallus is unicellular or multi-celled; in the
+higher forms it is often divided into stem and leaf. The sexual reproduction takes place in various ways; the sexual reproduction is effected by con-
+jugation of motile gametes, or by oogamous fertilization. The
+
+PROTOCOCCIDAE: 47
+
+warm-cells (zoospores, gametes, and spermatocysts) are con-
+structed symmetrical, and have three protophagous cilia, these
+generally being attached to the front end of the warm-cell.
+Most of these Algae live in water (fresh or salt); some are found
+upon damp soil, stones, or tree-stems, and some live enclosed in
+other organisms.
+
+The Class is divided into three families:
+
+1. **Protoocoecidae**: Volvoxaceae, Tetrasporaceae, Chloro-
+sphaeraceae, Phaeococcaceae, Protococcaceae, Hydrodytracaceae,
+Myriococcaceae, Ulvaceae, Ulvulaceae, Chlorellaaceae, Myriococcaceae,
+Cylindrocarpales, Chlorophyceae, Chlorophytae, Chlorophytae,
+Cladophoraceae, Gomontiaceae, Sphondyliaceae.
+
+3. **Siphonale**: Berytidiacae, Bryopodiacae, Berbisciae, Vau-
+cheriaceae, Phyllospiroaceae, Caulopercae, Codinaeae, Valoniaeae,
+Dactylococcaceae.
+
+Family 1. Protocoecidae
+
+The Algae which belong to this group are uni- or multi-cellular
+with the cells more or less firmly connected, sometimes in a definite,
+sometimes in an indefinite form (Fig. 47). Colonies are formed either by division of the individual cells or by the union of two or more individuals.
+The cell is usually spherical or ellipsoidal; the colony may be in this latter way termed a thallus. Apical cells and branching are absent. Multiplication by division; sexual reproduction by zoo-
+spores rarely by zoogamia. Sexual reproduction may be wanting, or it takes place in a monogenously rarely by zoogamia manner.
+
+Some are attached by means of a stalk to other objects (Chara-
+ciae; Fig. 49), others occur as "Endophytes" in the tissues of certain Mosses or Fennoscopes, e.g., Chlorodictyonum; some in Lemna
+(Trichoceros), Utricularia (Utriculina), Monostroma (Monostromata),
+and Peplispora; *Phylogymnium* in the leaves of *Lemna* nut-
+matoria; *Ajaea*, *Chlora*, and species of Grasses; *Sciolinophaera*
+in the leaves of *Hypnum* and *Lemna trinervia*; the remainder
+were formerly considered to belong to this family have been proved to be higher Algae in stages of development.
+
+Of the 10 genera mentioned in this order are either
+uni- or multi-cellular; and during the essential part of their life
+are free-swimming organisms. They are generally encased in a
+mucilaginous envelope, through which 2-6 cilia project from every w.a
+
+48
+PROTOCOCCODES.
+
+cell. The vegetative reproduction takes place by the division of all, or few, of the cells of the individual; in some a palmitic-stage is found in addition. The sexual reproduction takes place by isogamous or oogamous fertilisation.
+
+The Volvoxaceae may be considered to include the original forms of the Chlorophyceae, because, among other reasons, the motile stage is here the most promi-
+nent; thus the Volvox, which is a motile cell, is the only form intermediate to the Saprosporeae may perhaps be found amongst them.
+Three series of green Algae may be supposed to have taken their origin from the Volvoxaceae. The first series consists of the Chlamydomonads, whose conjugation is the nearest to the fertilisation in Chlorophyceae's palmita;
+the Pirococcocoeae in which the vegetative divisions have disappeared,
+while the sexual reproduction takes place through short spores—
+and Tetracarpaceae, in which the vegetative divisions are more prominent,
+whilst the swarming stage is less so.
+
+A. UNICELLULAR INDIVIDUALS. The principle genera are : Chla-
+mymodons, Spheroella, Phacotus.—Spheroella nivalis is the Alga
+which produces the phenomenon of " Snow," well known on
+high mountains and in ice and snow fields during winter months.
+The red colouring matter which appears in this and other green
+Algae, especially in the resting cells, is produced by the alternation
+of chlorophyll with carotinoides.
+
+Phacotus nivalis has an outer covering incrusted with lime,
+which, at death, or after division, opens out into two halves.
+Species may be found among Chlamydomonads, in which conjuga-
+tion takes place between gametes of similar size without cell-wall,
+or between gametes of different sizes. In some cases conjugation
+takes place between male and female splanagomates which are
+surrounded by a mucilaginous envelope.
+
+B. MULTICELLULAR INDIVIDUALS.
+The most important genera are Goniom, Stephanoicobrea, Pandor-
+inae. The Goniom has 3 or 5 cells arranged in a definite pattern in a flat plate (Fig. 44). Pandorina (Fig. 45),
+has 16 cells arranged in a sphere (Fig. 45).
+The sexual reproduction takes place in this way each cell, after having
+rounded off, and after the withdrawal of the cilia, divides itself
+
+![]() Fig. 45.—Goniom pandorina.
+
+PROTOCOCCOIDES.
+49
+
+into 16 new ones (Fig. 45 B), each forming a new individual,
+which soon grows to the size of the mother-individual. It was
+in this Alga that the conjugation of self-motile gametes was
+first discovered by Pringsheim, 1860. When conjugation is
+about to take place, each cell divides into sixteen, as in vegeta-
+tive reproduction, but the 16 x 16 cells do not separate from one
+another (Fig. 45 C, female gametes, and D, male gametes), and
+
+![]()
+A: A large cell with several smaller cells around it.
+B: A group of smaller cells.
+C: A cluster of small cells.
+D: A cluster of small cells.
+E: A cluster of small cells.
+F: A cluster of small cells.
+G: A cluster of small cells.
+H: A cluster of small cells.
+I: A cluster of small cells.
+J: A cluster of small cells.
+K: A cluster of small cells.
+L: A cluster of small cells.
+M: A cluster of small cells.
+N: A cluster of small cells.
+O: A cluster of small cells.
+P: A cluster of small cells.
+Q: A cluster of small cells.
+R: A cluster of small cells.
+S: A cluster of small cells.
+T: A cluster of small cells.
+U: A cluster of small cells.
+V: A cluster of small cells.
+W: A cluster of small cells.
+X: A cluster of small cells.
+Y: A cluster of small cells.
+Z: A cluster of small cells.
+AA: A cluster of small cells.
+AB: A cluster of small cells.
+AC: A cluster of small cells.
+AD: A cluster of small cells.
+AE: A cluster of small cells.
+AF: A cluster of small cells.
+AG: A cluster of small cells.
+AH: A cluster of small cells.
+AI: A cluster of small cells.
+AJ: A cluster of small cells.
+AK: A cluster of small cells.
+AL: A cluster of small cells.
+AM: A cluster of small cells.
+AN: A cluster of small cells.
+AO: A cluster of small cells.
+AP: A cluster of small cells.
+AQ: A cluster of small cells.
+AR: A cluster of small cells.
+AS: A cluster of small cells.
+AT: A cluster of small cells.
+AU: A cluster of small cells.
+AV: A cluster of small cells.
+AW: A cluster of small cells.
+AX: A cluster of small cells.
+AY: A cluster of small cells.
+AZ: A cluster of small cells.
+BA: A cluster of small cells.
+BB: A cluster of small cells.
+BC: A cluster of small cells.
+BD: A cluster of small cells.
+BE: A cluster of small cells.
+BF: A cluster of small cells.
+BG: A cluster of small cells.
+BH: A cluster of small cells.
+BI: A cluster of small cells.
+BJ: A cluster of small cells.
+BK: A cluster of small cells.
+BL: A cluster of small cells.
+BM: A cluster of small cells.
+BN: A cluster of small cells.
+BO: A cluster of small cells.
+BP: A cluster of small cells.
+BQ: A cluster of small cells.
+BR: A cluster of small cells.
+BS: A cluster of small cells.
+BT: A cluster of small cells.
+BU: A cluster of small cells.
+
+50
+PHOTOCOCCIDAE.
+
+has at first a large colourless anterior end, 4 cilia, and 2 "eye-
+spores" (Fig. 45 G), but these soon disappear and the cell becomes
+uniformly dark-green and spherical, and surrounds itself with a
+thick cell-wall, losing at the same time its power of motion: the
+zygote (Fig. 45 H) is formed, and becomes later on a deep red
+colour. The zygote divides into two daughter cells, whose
+contents burst open the wall (Fig. 45 J), and emerge as a large
+swarmspore (Fig. 45 K) which divides into 16 cells, and the first
+small individual is formed (Fig. 45 L, M).
+
+*Endocystis* is like *Pandorina* in structure, but stands somewhat
+
+**Fig. 45.** *Folus globus*, sexual individuals ; *a* zoosporic which have formed spermato-
+sides ; *b* oogonium.
+
+higher, since the contract between the conjugating sexual cells is
+greater, the female one being a motile zoospore.
+
+The habit of this species is shown in Fig. 46.
+
+The cells are here arranged on the circumference of a sphere, and
+enclose a cavity filled with mucilage. The number of these cells
+may vary from 300-2500, of which the majority are vegetative
+and not nutritive, but some may lay down large masses of mucilage
+(Fig. 46 b); others, which may appear as solitary individuals,
+divide and form disc-shaped masses of from 8-256 small spermato-
+
+PROTOCOCCACEAE. 51
+
+zooids (Fig. 46 c). After the zoosphere has been fertilized by these, the zoosphere surrounds itself by a thick, sometimes thorny cell-wall, and on germination becomes a new individual of few cells.
+A few cells conspicuous by their larger size may be found (1-8, but generally 8) in certain individuals, and these provide the vegeta-
+tive division of the colony. The zoosphere is usually sessile.
+
+Order 3. Tetraprotococcaceae. These reproduce both by vegetative divisions and swarmsomes, some have also gamete-conjugation. The principal genera are:
+Tetraporus, Aplastodiscus, Dictyochlorella, Dictyopharum, Chloromagnus,
+Chlorococcus, Chlorocystis.
+
+Order 4. Pterococcaceae. In this order the swarming stages and sexual reproduction are entirely absent. Vegetative repro-
+duction by division. The principal genera are: Pterococcus (Fig.
+47), Sphaeromonas (Fig. 48), Raphidium, Oxyceps, Schizochytrium,
+Corynothrix, Chlamydosporium. Pterococcus is one of the most common Algae throughout the world, occurring as green
+coverings on tree-stems, and damp walls, and it is one of the most
+common lichen-gondia.
+
+
+
+Order 5. Protococcaceae. The cells are motionless, free or
+affixed on a stalk (e.g. Characium, Fig. 40), either separate or
+loosely bound to one another; they never form multicellular
+individuals. Multiplication by division is very rare. Reproduction takes
+place by swarmsomes, which have 1 or 2 cells,
+and sexual reproduction in some by gamete-
+conjugation. The principal genera are: Chlo-
+rosporella, Chlorocystis, Chlorophyllum, Scuticaria,
+Ophiogymnion, Scuticium.
+
+Order 6. Hydrodictyaceae. The indi-
+viduals are unicellular and remain until after
+the zoospore-stage is definitely formed;
+families (comodo). Ordinary vegetative division is wanting, but
+
+
+
+51
+
+52
+PHOTOGONODEM.
+
+asexual reproduction takes place by zoospores (or by motoneless cells without cilia), which unite and form a family similar to the mother-family, inside the mother-cell in a multinucleated envelope. Where sexual reproduction is found it takes place by gamete-conjugation. The principal genera are : Podiatræum (Fig. 30), Caudatærum, Hydrodromus (Fig. 31).
+
+The genus Podiatræum, Hydrodromus, *Heterotricha* *solatium* (Water-net) is formed of a large number of cells which are cylindrical, and attached to one another by the ends (Fig. 51). The asexual reproduction takes place by zoospores, which are formed in large numbers, and which swim about for a time, and then come to rest and arrange themselves into a new net (Fig. 51 a) which is set free by the dissolution of the wall of the mother-cell, grows, and becomes a new cell.
+
+Fig. 31. - Podiatræum *superbum.*
+
+**Fig. 31. - Zoospores conjugation.**
+
+A. A zoospore of *Podiatræum* *superbum*. B. A zoospore of *Hydrodromus* *solatium*. C. A zoospore of *Heterotricha* *solatium*. D. A zoospore of *Heterotricha* *solatium*. E. A zoospore of *Heterotricha* *solatium*. F. A zoospore of *Heterotricha* *solatium*. G. A zoospore of *Heterotricha* *solatium*. H. A zoospore of *Heterotricha* *solatium*. I. A zoospore of *Heterotricha* *solatium*. J. A zoospore of *Heterotricha* *solatium*. K. A zoospore of *Heterotricha* *solatium*. L. A zoospore of *Heterotricha* *solatium*. M. A zoospore of *Heterotricha* *solatium*. N. A zoospore of *Heterotricha* *solatium*. O. A zoospore of *Heterotricha* *solatium*. P. A zoospore of *Heterotricha* *solatium*. Q. A zoospore of *Heterotricha* *solatium*. R. A zoospore of *Heterotricha* *solatium*. S. A zoospore of *Heterotricha* *solatium*. T. A zoospore of *Heterotricha* *solatium*. U. A zoospore of *Heterotricha* *solatium*. V. A zoospore of *Heterotricha* *solatium*. W. A zoospore of *Heterotricha* *solatium*. X. A zoospore of *Heterotricha* *solatium*. Y. A zoospore of *Heterotricha* *solatium*. Z. A zoospore of *Heterotricha* *solatium*. AA. A zoospore of *Heterotricha* *solatium*. BB. A zoospore of *Heterotricha* *solatium*. CC. A zoospore of *Heterotricha* *solatium*. DD. A zoospore of *Heterotricha* *solatium*. EE. A zoospore of *Heterotricha* *solatium*. FF. A zoospore of *Heterotricha* *solatium*. GG. A zoospore of *Heterotricha* *solatium*. HH. A zoospore of *Heterotricha* *solatium*. II. A zoospore of *Heterotricha* *solatium*. JJ. A zoospore of *Heterotricha* *solatium*. KK. A zoospore of *Heterotricha* *solatium*. LL. A zoospore of *Heterotricha* *solatium*. MM. A zoospore of *Heterotricha* *solatium*. NN. A zoospore of *Heterotricha* *solatium*. OO. A zoospore of *Heterotricha* *solatium*. PP. A zoospore of *Heterotricha* *solatium*. QQ. A zoospore of **Podiatræum** **superbum**.
+
+The sexual reproduction takes place by gamete-conjugation.
+The gametes are formed in the same manner as the zoo-
+spores, but in larger numbers (30,000-100,000), and swarm out
+of the mother-cell (Fig. 51). The sygote forms, on germination,
+2-3 large thorny bodies (polyhedra); these swarm about for a time,
+and after a period of rest become irregular thorny bodies (polyhedra);
+their contents again divide into zoo-
+spores, the thorny external coating
+of the polyhedra is cast off,
+and the exosporae, surrounded by the dilated internal coating,
+mute to form a small family, which produces several others in the
+manner described.
+
+Fig. 31.
+
+**CONFEROIDEA.**
+
+**53**
+
+**Family 2. Confervoideæ.**
+
+The individuals are always multicellular, the cells firmly bound together and united into unbranched or branched filaments, expansions, or masses of cells which grow by intercalary divisions or by the growth of new cells from the base. The filaments are unicellular, but the cells of the remaining three orders contain several nuclei. Asexual reproduction by zoospores, akinetes, or aplanospores. Sexual reproduction by isogamous or oogamous fertilization.
+
+The Confervoidæ, through the Ulvaceae, are connected with the Tetra-
+sporeae, and from the Chlorococcales, which is the most highly developed order of the Ulvaceae, they pass to the Siphonales, which do not take their origin. The Chlorococcales show the nearest approach to the Siphonale.
+
+Order 1. *Ulvacea*. The thallus consists of one or two layers of parenchymatous cells, connected together to form either a flat membrane (Monostroma, Ulva) or a hollow tube (Enteromorpha), and in some cases a third layer of cells is formed. This section takes place by detached portions of the thallus; or sexually by zoospores or akinetes. Gamete-conjugation is known to take place in some members of this order, the zygote germinating within the resting-stage. The majority are found in salt or brackish water.
+
+Order 2. *Ullothricacea*. The thallus consists normally of a simple unbranched filament (sometimes a small expansion con-
+![]()
+A diagram showing a portion of a filament with zoospores.
+
+
+Fig. 31.—*Ulvoidea scandens*, a portion of a filament with zoospores, which are formed two in each cell (zoosporangia); the dark spots are the red "exopores". 1, 2, 3, 6 denote successive stages in the development of the zoospores; b a single zoospore; e an exopore; f an exopore with a zoospore; g an exopore with an exosporangium; h two gametes; i two gametes; j an exopore with an exosporangium; k an exopore with an exosporangium and a gamete; l an exopore with an exosporangium and two gametes; m an exopore with an exosporangium and two gametes; n an exopore with an exosporangium and two gametes; o an exopore with an exosporangium and two gametes; p an exopore with an exosporangium and two gametes; q an exopore with an exosporangium and two gametes; r an exopore with an exosporangium and two gametes; s an exopore with an exosporangium and two gametes; t an exopore with an exosporangium and two gametes; u an exopore with an exosporangium and two gametes; v an exopore with an exosporangium and two gametes; w an exopore with an exosporangium and two gametes; x an exopore with an exosporangium and two gametes; y an exopore with an exosporangium and two gametes; z an exopore with an exosporangium and two gametes.
+
+
+siting of one layer of cells is formed, as in *Sokomorée* and *Prasola* which were formerly described as separate genera). Asexual reproduction takes place by means of zoospores (with
+
+54
+CONTEINERIDAE.
+1, 2, or 4 cilia), akinetes or aphanospores; the last named may germinate immediately, or only after a period of rest. Sexual re-
+production takes place by the conjugation of gametes of about the same size, each having two cilia (Fig. 52 d). The zyocyte of Ulothrix, on germination, produces a brood of zoospores which swarm in the water, and then become attached to the substrata (alteration of generations). The gametes may also germinate without conjugation in the same manner as the zoospores. The principal genera are : *Ulothrix*, *Harmadum*, *Conferma*, *Mecu-
+spora*. The latter is very rare, and runs fresh water. Nearly all the species of *Conferma* occur in fresh water, stems and stones.
+
+Order 3. *Chlorophyceae.* The thallus consists of a single,
+branching, or creeping filament of cells, often surrounded by mucilage. The cells have only one nucleus. Asexual reproduction by zoospores with 2 or 4 cilia, by akinetes, or aphanospores. In many, conjugation between gametes with 2 cilia may be found. They approximate to the *Characeae* and *Cyanophyceae*.
+
+The principal genera are : *Stigmacoccus*, *Drapetosilus*, *Chetophora*, *Eutropha*, *Aphanochroa*, *Hypertoxia*, *Phoridium*, *Chlorotrichium*, *Pirichthysia*, *Glycinea*, *Trentepohlia*. Most of the species are greenish in colour, but some are red. A red
+colouring material, which occurs in addition to the chlorophyll, they are aerial algae which live on stones (*T. jolitha*, "violin stone," so named on account of its violet-like odour in rainy weather), on rocks ("Pirichthysia verdelis"), or on the rocks ("Pirichthysia verdelis" lives in the Bristish Isles).
+
+Order 4. *Myxococcales.* The thallus is discoid, consisting of one or more
+collaterals, and is always attached. Asexual reproduction by zoospores with 2
+or 4 cilia. Sexual reproduction in some species by the conjugation of gametes
+with 8 or 16 cilia (Fig. 53 b). The genus is represented by *Myxococcus* and
+*Colochocearhiza*. The species occur in fresh water (*Chelatella*) as well as in salt (*Prismatoceros*), on the surface of the earth (*Dermatocystis* = *Epidermocystis*), and on the leaves of tropical plants, destroying the leaf-nuts (Myrsidea).
+
+Order 5. *Cylindrocapsaceae.* The thallus consists of a simple
+(rarely, in parts, formed of many rows) unbranched filamentous body, covered with a single nucleus, and is enveloped in a thick envelope with a laminated structure. Asexual reproduction by zoospores with 2 cilia, which are formed 1, 2 or 4 in each vegetative cell. The
+
+55
+
+*Confervidae.*
+
+*Antheridia* are produced by a single cell, or a group of cells, in a filament, dividing several times without increasing in size. Two egg-shaped spermatocysts, each with 2 cells (Fig. 53 D), are formed in each *antheridium*, and escape through an aperture in the side; in the first stages they are enclosed in a bladder-like sac.
+
+**Fig. 53 B, C.** Other cells of the filament swell out into two segments (Fig. 53 A) which resemble those of *Odlogonium*. After fertilisation the zoospore surrounds itself with a thick wall, and assumes a greenish colour.
+
+The germination is unknown. The unfertilised zoospores remain green, divide often into 2 daughter-cells, and grow into new filaments.
+
+This order, which only includes *Oedlogonium*, *Oplodiscus*, forms the connecting link between *Ulothrixis* and *Eudogonium*. The few species (4) occur only in fresh water.
+
+Order 6. *Edlogoniaceae.* The thallus consists of branched filaments, usually unbranched (*Edlogonium*) filaments, attached in the early stages. The cells may be longer or shorter, and have one nucleus. Asexual reproduction by zoospores, which have a caplet of cilia round the base of the colourless end (Fig. 6 a). *Sexual reproduction* takes place by conjugation, fertilisation. On the division of the zoospore, 2 zoospores are formed (Fig. 54 F). They occur only in fresh or slightly brackish water. The division
+
+![]() A diagram showing the structure of an antheridium.
+![]() B and C show two segments of a filament.
+![]() D shows a spermatocyst with two cells.
+
+56
+
+CONVERGENCE.
+
+of the cells takes place in quite a peculiar and unusual manner.
+At the upper end of the cell which is about to divide, a ring-shaped thickening of soft cellulose is formed transversely round the wall; the cell-nucleus of the mother-cell and the protoplasm then divide by a transverse wall into two portions of similar size, and the cell-wall bursts transversely at this line of division, leaving a conical or conical-triangular line of the thickened ring. The cell-wall thus divides into two parts, one short, the "cap," and the lower one much longer, the "stalk." The divisions of the original cell-wall now separate from each other, the cell-nucleus being left in the stalk, and supplying an additional length of cell-wall between the two new cells. This stalk will project a little in front of the piece thus inserted. Thus, between the two new cells is formed near to the uppermost edge of the sheath, and gradually becomes thicker and firmer.
+
+The inserted piece of wall is called the "cap," and is part of the wall of the upper cell: the remainder is formed by the calf. This mode of division is repeated exactly in the same way, and new caps are formed close below the first one, for every division.
+
+![]()
+A female plant with three reduced ovaries (a) and three ovules (b). The ovule with spermatium (c) soon entering the capsule (d) has just been fertilized by pollen (e), and is developing into a seed (f). B Ovary with three ovules (g), one of which spermatium (h) is emerging. C Portion of flower with three ovules (i), one of which spermatium (j) is emerging. D Portion of flower with three ovules (k), one of which spermatium (l) is emerging. E Portion of flower with three ovules (m), one of which spermatium (n) is emerging. F Portion of flower with three ovules (o), one of which spermatium (p) is emerging. G Portion of flower with three ovules (q), one of which spermatium (r) is emerging. H Portion of flower with three ovules (s), one of which spermatium (t) is emerging. I Portion of flower with three ovules (u), one of which spermatium (v) is emerging. J Portion of flower with three ovules (w), one of which spermatium (x) is emerging. K Portion of flower with three ovules (y), one of which spermatium (z) is emerging.
+
+
+CONFERSVIGIDEA.
+
+Fortification takes place in the following way. The coenoom is a large ellipsoidal, swollen cell (qg, in Fig. 54 A), whose contents are rounded off into an oosphere with a colourless receptive-spot (see B); an aperture is formed in the wall of the oogonium, through which the spermatzooids are enabled to enter (B). The spermatzooids are then conveyed by the basal cells of the filament, or indirectly. In the latter case a swarm-spore (androgam) is formed which comes to rest, attaches itself
+
+![]() A small, round, brownish object with a central dark spot.
+57
+
+Fig. 53.—Cocconate pulvinoida. A A portion of a thallus with organs of reproduction ; B a young sporophyte ; C a mature sporophyte ; D, A, B, m., with energy-irreversible ; E Bipe cocconate, with envelope. Characters of the sporophyte. D Raspone. E spermatocline.
+
+to an oogonium, germinates, and gives rise to a filament of a very few cells—dicaric-formula (A, B, m.). The spermatzooids are formed by the summit of the antheridium lifting off like a lid. On the germination of the oospore (Q), which takes place in the following spring, 4 zoospores are produced (P), i.e. the sexual generation; these are liberated by the rupture of the envelope of the oospore.
+
+Order 7. *Coleochetaceae.* The thallus is always attached, and of a disc or cushion-shape, formed by the dichotomous branching of filaments of cells united in a pseudo-parenchy- mal layer. The sexual generation is effected by internal re-production by zoospores with 2 cilia (Fig. 55 D), which may arise in all the cells. Sexual reproduction by coenoom fertilisation. The spermatzooids resemble the swarmspores, but are
+
+58
+
+**COXERYGIDEA.**
+
+smaller (E), and originate singly (in the species figured) in small conical cells (c. d in A). The oogonia are developed at the extremities of certain branches; they are bottle-shaped cells with very long and thin necks (trichogone), open at the end (a in A); at the base of each oogonium is a spherical oosphere. The spor-
+matization takes place by means of a protoplast which passes through an aperture in the wall when the trichogone is absent, and fertilisation having taken place, the oogonium becomes surrounded by a cell-layer (envelope), which grows out from the cells near its base (b in A), and in this way a kind of fruit is formed (B) (sporocarp, *eyerythra*).
+
+The oospore, next spring, divides and forms a parenchymatous tissue (homologous with the *Mose-spongyphyte*); this bursts open the envelope, and the oospores are liberated, with the spores of the *Mose-capsule* arises in each of the cells, and form a *Colocheite*. We have then, in this case, a still more distinct alternation of generations than in *Oedogonium*. Only one genus, *Colocheites*, is known, but it contains several species, all living in water.
+
+Order 8. **Cladophoraceae.** This order is probably derived from the *Ulothricaceae*. The thallus consists of a single, un-
+branched or branched filament, generally with an apical cell. The cells have each 2 or more nuclei. Sexual reproduction by zoospores is unknown; but there is akinetic formation of gametos with 2 cilia is found in some genera. They occur in salt as well as in fresh water. The principal genera are: *Urospora*, *Chloromorphus*, *Zelkonomus*, *Cladophora*; of the last named genus the oospore is a large, thick-walled body common to salt water; *C. fruticis* and *C. glomerata* in fresh water.
+
+Order 9. **Goniomonaceae.** *Goniomonas polytricha*, the only species hitherto known, is found on old calcareous shells of certain salt water Molins.
+
+Order 10. **Sphéroplacaceae.** The thallus consists of free, un-
+branched filaments, with very elongated multinucleate cells. Vegetative reproduction by zoospores; sexual reproduction by oogonial fertilisation (see page 13, Fig. 10 D). The oospore has a thick wall (Fig. 10 D) studded with warts, and assumes a colour like that of the parent plant. It germinates in spring, and produces 1-8 zoospores, each with 2 cilia (Fig. 10 E), which grow into new filaments. Only one species, *Sphéroplaca anulosa*, is known.
+
+![]() A diagram showing the structure of a Cladophora-like organism.
+
+**Siphonacee.** 39
+
+Family 3. Siphonace.
+
+The thallus has apical growth, and in the vegetative condition consists generally of one single (in the Valoniacae most frequently of more) multinucleate cell which may be much branched, and whose separate parts in the higher forms (e.g. Bryopsis, Fig. 57 ; *Caulerpa*, Fig. 50, etc.) may be differentiated to perform the various physiological functions (as root, stem and leaf). Vegetative reproduction is by means of the zygote (gametous); sexual reproduction by zoospores, akinetes, or aphanopores. Sexual reproduction by gamete-conjugation, rarely by oogamous fertilisation. The zygote or copore germinates as a rule without any resting-stage.
+
+Most of the Siphonaceae occur in salt water or on damp soil.
+
+Fig. 58.—*Bryopsis* *glandulosa*. a an entire plant forming *sarcopodium*; b a *sarcopodium*; c an individual with *gametous*; d *z.g.* conjugation; e *z.g.* conjugation; f a *zygote*.
+
+Many (e.g. *Dugaldiaceae*) are very much increased with lino, and occupy the fossilised condition, in the deposits from the Cretaceous period to the present time. The Siphonaceae are connected by their lowest forms (*Botrydiaceae* or *Valoniae*) with the Protoococcaceae, but show also, through the Valoniacae, points of relationship to the *Chlorophyceae*.
+
+Order I. Botrydiaceæ. The thallus in the vegetative condition is unicellular, club-shaped, with a small round (*Caulidium*) or repeatedly dichotomously branched system of colourless rhizoids (*flagellum*), by which it is attached to objects immersed in salt water (*Caulidium*); or to short stipes (*Botrydium*). Asexual reproduction by zoospores with one (*Botrydium*) or two
+
+![]() A diagram showing the structure of a Siphonaceae thallus.
+
+60
+Siphonaceae.
+
+cilia, and by aphanospores. The sexual reproduction is only known in *Bryopsis*, and takes place in the following manner: in the part of the thallus which is above ground and in an active vegetative condition, several round cells (Fig. 56 c) are formed, which may be green or red according as they grow under water, or exposed to air. These cells are called "gametangia" and considered as "gametangia" as they produce many gametes (a) provided with two cilia. The zygote (b, c) formed by the conjugaion (e, f, g) may either germinate immediately, or become a thick-walled resting-cell of an irregular angular form.
+
+Order 3. Bryopodiaceae. The thallus in the vegetative condition is uni- cellular, and consists of a single irregularly branched cell at the lower extremity of branched filaments. A portion of this upper portion is prolonged into a stem-like structure of un- known nature, bearing terminal branches, acrospores, and leaf-like structures. The acrospores are produced in the upper part of the stem, and are separated by a cross- wall from the stem, and become free. The acrospores are of two kinds: one large and one small. Zoospores or any other method of sexual reproduction are unknown. Only one genus, *Bryopsis*, living in salt water.
+
+Order 4. Derbesiaceae. Only one genus, *Derbesia*, living in salt water. The thallus is a single cell, which has arisen through the coalescence of several, and they resemble the zoospores of *Euglena* by having a circle of cilia attached at the base of its columnar body.
+
+Order 5. Vaucheriaceae. The thallus consists in the vegetative condition, of a single irregularly or dichotomously branched cell, without differentiation into stem or leaf; root-like organs of attachment may however occur. Asexual reproduction by zoospores, which are formed singly in the extremity of a branch cut off by a transverse wall, containing many nuclei, and bear small cilia situated in pairs, which give the appearance of a fine pile covering the whole or a great part of the surface. Akinides,
+
+![]() Fan 47.--Bryopsis pinnacea. A, the plant; natural size.
+B, a portion (enlarged) which shows the growing point
+ofthelower derived from its apical vegetative
+extension.
+C, colour and smaller. Zoospores or any other method of sexual reproduction are unknown.
+Only one genus, Bryopsis, living in salt water.
+
+Siphonaceae. 61
+
+Aplanospores, and phytozomebe (naked masses of protoplasm, without cilia), which creep like an ameba on a substratum) may occur under certain conditions.
+
+The sexual reproductive organs are formed on short lateral branches and are separated from the vegetative cell (Fig. 65 A) by cell-walls. The spermatocysts, each with two cilia, are developed in the coiled antheridium (A, b). The oogonium is a thick, egg-shaped, often oblique cell, with its protoplasm rounded into a globule. The egg is a hyaline nucleus (A, a) imme-
+diately beneath the aperture formed in the wall of the oogonium. A slimy mass, which serves to receive the spermatocysts, is formed in some species in this aperture. The spermatocysts when liberated swim towards and enter the oosphere, which then immedi-
+ately surrounds itself with a thick cell-wall. The mature oospore (B) contains a large quantity of oil. At germination the outer cell-wall bursts and a new plant is formed. There is only one known species living in salt as well as in fresh water and on damp soil.
+
+Order 5. Phyllophoraceae are parasites in the leaves and stalks of flowering plants.
+
+Order 6. Caulerpaceae. The thallus has distinct differentiation into root, stem, and leaf-like members (Fig. 69) it is unilocular. With the exception of one species branched threads of cell-lime extend from one side to the other serving as stays to support the thallus. Reproduction takes place by detached portions of the thallus; no other modes of reproduction are known. This order may be considered as a primitive form of lichenoid growth. The genus *Caulerpa* consists of more than seventy species which inhabit the tropical seas.
+
+Order 7. Codiaceae. The thallus has various forms, but with-
+
+62
+Siphonae.
+out distinct differentiation in stem- or leaf-structures, sometimes (e.g. *Halimod*) it is very much increased with time. In the early stages it is multicellular (later, often multilocular), very much branched, with the branches, at any rate partly, so united or grown in amongst one another (Fig. 60) that an apparently purely vegetative reproduction is formed. *Subjects* of *siphonae* are wanting; zoospores (or gametes?) may be developed in some species, however, in special swollen cells, which are similar to that in *Drosera* occurs perhaps in *Coltium*. They are all salt water forms.
+
+Order 8. Valoniaceae. The thallus is generally multinucleate, without differentiation into stem- or leaf-structures, but the cells are united together and form a leaf-like reticulate expansion (e.g. *Anodymena*). Zoospores are produced by the cells, and they are then formed directly in the vegetative cells. In others (e.g. *Falcaria*) the zoospores, which may be separated through the damaging of a cell, can surround itself with
+
+![]() A diagram showing a plant structure with multiple branches and cells.
+Fig. 60.—*Onodera prolifera* (natural size).
+
+a cell-wall, and grow into a new plant. No other modes of reproduction are known. The most important genera are: *Falunia*, *Siphonodendron*, *Chamederta*, *Strouma*, *Heterostoma*, and *Anodymena*.
+
+As already pointed out, the Valoniaceae occupy a somewhat central position among the Siphonae. They are closely related to the *Bryophyta* through *Bryocladon* and the *Bryopteridaceae* through *Falunia*, with the *Dactylotum* through *Chamederta*, and also with the *Cladophoraceae* through *Siphonodendron*, and *Strouma*.
+
+Siphonae. 63
+
+Order 9. *Dasycladaceae.* The thallus consists of an axile longitudinal cell, destitute of transverse walls, attached at the base by root-like organs of attachment, and producing acropetally a short stem, which bears a fertile leaf, and a sterile leaf with limited growth. Axonal reproduction is wanting. Sexual re-production by conjugation of gametes which arise in separate, fertile leaves, either directly or from siphonouspores, which develop into naked gametangia. The principal genera are : *Acotoborula,* *Dasy-cladus,* *Nemocera,* *Cymopedia.* All marine.
+
+The curiously shaped *Acotoborula mediterranea* (fig. 60) grows on limestone rocks, and shells of mussels in the Mediterranean; it re-sembles a small beehive with a small stem, sometimes as much as nine centimetres in length, and one centimetre in diameter. The cell-membrane is thin, and incrustated with carbonate and oxalate of lime.
+Only the lower, roof-like part of the thallus, which penetrates the calcareous substratum survives the winter, and may grow up into a new thallus. The leaves, which grow off the stem, are dichotomyously branched and formed of cylindrical cells separated from each other by cross-walls, but they are not grown together. The fertile leaves are formed by a circle of 70-100 cup-shaped rays (fertile leaves) growing out from the stem. 40-80 siphonospores are formed, which become liberated at the breaking of the shade, and later on are changed to gametangia (compare *Bryo-dawn*) which open by a lid and allow a large number of egg-shaped gametes with two cilia to escape. Gametes from various
+
+![]() A: A small beehive-like structure with a stem.
+![]() B: A magnified view of the beehive-like structure showing its internal structure.
+
+Fig. 60.—*Acotoborula mediterranea.* Plant (natural size). B Part of a longitudinal section.
+
+G4
+CHARACEE.
+gametangia conjugate with one another; the product of the conju-
+gation swarms about for some time, rounds off, and then surrounds
+itself with a cell-wall. The zygoth germinates after a period of
+rest and then produces a sexual plant. The aplanospores (game-
+tangia) thus represent the sexual generation.
+
+Class 7. Characeae.
+The thallus has a stem with nodes and internodes; and whorls
+of leaves, on which may be developed the antheridia and oogonia,
+are borne at the nodes. Vegetative reproduction by bulbils and
+accessory buds, and by spores, are common. The spores are
+spherical, and contain a number of flagella in which the spirally
+called spermatoida, each with two cilia, are formed. The oogonium is situated terminally, and is first naked, but becomes later
+on surrounded by a investment, and forms after fertilisation the
+so-called "fruit," the zygote. The zygote develops into a plant by producing a "proembryon," from which the young sexual plant arises as a lateral branch. The Characeae are distinguished by the structure of their vegetative system as well as by the spirally-
+coiled sporangia. The Siphonocarpaceae are included in the Order of
+Thallophytes, of which, however, the Siphonaceae appear to be their nearest relations. They were formerly, but wrongly, placed near the Mosses. The class contains only one order, the Characeae.
+
+Order 1. Characeae. Algae with a peculiar colour, often increased with greenish tints, and growing gregariously in large masses at the bottom of fresh and brackish water, and are from a few inches to more than a foot in height.
+The stem has long internodes which in *Nidula* are formed of one cylinder enclosing another smaller one; the cells are separated by a cortical layer of smaller ones. The protostem in contact with the cell-wall exhibits in a well-marked degree the movement of rotation (cyctosis), carrying the chlorophyll corpuscles along with it. In *Chara*, the leaves are produced in whorls of small cells (nodal cells) from which the leaves are produced. The leaves are borne in whorls of from 5-12 which regularly alternate with one another as in the higher vertebrate plants; a branch grows out in the axil of the first-formed leaf of each whorl (Fig. 61 A., n.).
+
+The leaves are constructed in the same manner as the stem; they are divided into a series of joints, but have only a limited
+
+CHARACEE. 65
+
+power of growth; their terminal cell, too, is not enclosed by a cortex. Leaflets are borne at their nodes. The growth of the stem is unlimited, and proceeds by means of an apical cell (Fig. 62 a) which divides into two cells, one lying above the other; the lower one, without
+
+any further division, becomes one of the long, cylindrical, internodal cells (Fig. 62 a), and the upper one (Fig. 62 a) divides by transverse walls into two segment-cells (Fig. 62 b). These segment-cells divide again by transverse walls into new apical cells. The segment-cell then divides by a transverse wall into two cells, one lying above the other; the lower one, without
+
+![]()
+A Portion of a plant, natural size.
+B Portion of a leaf A, with leaflets A-37'; a nucellusiform ; e squamule.
+C A shield--Nidula fascia.
+D Filaments from antheridia with operculum.
+E Free spermatium.
+
+
+Fur. 61.--Chora fragilis. A Portion of a plant, natural size. B Portion of a leaf A, with leaflets A-37'; a nucellusiform ; e squamule. C A shield--Nidula fascia. D Filaments from antheridia with operculum. E Free spermatium.
+
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