The Collaborative International Dictionary of English v.0.48:

Scaphognathite \Sca*phog"na*thite\, n. [Gr. ska`fh boat +
   gna`qos jaw.] (Zool.)
   A thin leafike appendage (the exopodite) of the second
   maxilla of decapod crustaceans. It serves as a pumping organ
   to draw the water through the gill cavity.
   [1913 Webster]