pseudobranchial

from The Collaborative International Dictionary of English v.0.48

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.
   [1913 Webster]