The Collaborative International Dictionary
Pseudobranchia
Pseudobranchia \Pseu`do*bran"chi*a\, n.; pl. Pseudobranchi[ae]. [NL. See Pseudo-, and Branchia.] (Anat.) A rudimentary branchia, or gill. -- Pseu`do*bran"chi*al, a.
Wiktionary
pseudobranchia
n. (label en marine biology) A small patch of gill-like filaments on the inner surface of the opercle near the junction of the preopercle.