The Collaborative International Dictionary of English v.0.48:

Aprocta \A*proc"ta\ ([.a]*pr[o^]k"t[.a]), n. pl. [NL., fr. Gr.
   'a priv. + prwkto`s anus.] (Zool.)
   A group of Turbellaria in which there is no anal aperture.
   [1913 Webster]