'Pygobranchia' definitions:

Definition of 'Pygobranchia'

From: GCIDE

Pygobranchia \Py`go*bran"chi*a\, n. pl. [NL., fr. Gr. pugh` the rump + ? a gill.] (Zool.) A division of opisthobranchiate mollusks having the branchi[ae] in a wreath or group around the anal opening, as in the genus Doris. [1913 Webster]