opisthobranch, n. (a.) Zool.
(əʊˈpɪsθəbræŋk)
[f. mod.L. Opisthobranchia neut. pl., f. opistho- + Gr. βράγχια gills.]
An opisthobranchiate gastropod: see next. b. adj. = next.
| 1851–6 Woodward Mollusca 50 The sexes are..united in the (monœcious) land-snails, pteropods, opisthobranchs, tunicaries, and in part of the conchifers. 1877 Huxley Anat. Inv. Anim. viii. 511 No Opisthobranch possesses a large visceral sac of this kind. |
Hence oˈpisthoˌbranchism, the condition of being opisthobranchiate.