The Collaborative International Dictionary of English v.0.48:

Lamellibranchiate \Lam`el*li*bran"chi*ate\, a. (Zool.)
   Having lamellar gills; belonging to the Lamellibranchia (also
   called Pelecypoda). -- n. One of the Lamellibranchia (also
   called Pelecypoda).
   [1913 Webster]