sentence: Crinoids have a mouth on the top surface that is surrounded by feeding arms.
sentences_before: All crinoids are marine, and live both in shallow water and in depths as great as 6000 meters. The basic echinoderm pattern of fivefold symmetry can be recognized, but most crinoids have many more than five arms.
concept_name: crinoid
headings: Crinoidea
categories: Echinoderms