opisthocomous (opisthokomus)

[NL. opisthocomus, behind, + κόμη, the hair: see coma2.] Having an occipital crest, as the hoactzin. Opisthocomus (op-is-thok'ō-mus), n. see opisthocomous.] The only known genus of J. Smit Hoactzin (Opisthocomus cristatus). [NL.: Opisthocomida. There is but one species, O. hoactzin or O. cristatus, of South America. See hoactzin. Also called Orthocorys and Sasa. opisthodome (ō-pistho-dom), n. [ mos, q. v.] Same as opisthodomos. opisthodomos, opisthodomus (op-is-thod'ō. mos, -mus), n. [ order of Gasteropod a having the gills behind the heart: opposed to Prosobranch i at a. They have a relatively large foot and small visceral hump, short mantle-flap, behind which is the anus. They are usually shell-le in the adult state, and many of them lose the ctenidial gills and mantle-flap, respiration being effected by very diversiform supplementary organs. Hence the equally various methods of subdivision of the order, and the application to its divisions of exceptionally numerous names ending in -branchia. The opisthobranchs are marine and littoral gastropods of more or le slug-like aspect, and many of them are known as sea - slugs, sea - hares, sea-lemons, etc. See Nudibranch i at a, Tectibranch i at a. opisthobranch i ate (o-pis-tho-brang'ki-āt), a. and n. I. a. In Mollusca, having the gills in such a position that the blood must take a forward course to reach the heart. II. n. An opisthobranch.