sentence: Colleoid cephalopods have complex organs which they use to change colour rapidly.
sentences_after: This is seen in squid, cuttlefish and octopuses. Each chromatophore unit is a single chromatophore cell and muscle, nerve, glial and sheath cells. Inside the chromatophore cell, pigment granules are in an elastic sac. To change colour the animal changes the sac form or size by muscular contraction. This changes its appearance.
concept_name: colleoid cephalopod
headings: Chromatophore Cephalopod chromatophores
categories: Ecology Physiology