The Collaborative International Dictionary of English v.0.48:

Enteropneusta \En`te*rop*neus"ta\, n. pl. [NL., fr. Gr.
   'e`nteron an intestine + ? to breathe.] (Zo["o]l.)
   A group of wormlike invertebrates having, along the sides of
   the body, branchial openings for the branchial sacs, which
   are formed by diverticula of the alimentary canal.
   Balanoglossus is the only known genus. See Illustration in
   Appendix.
   [1913 Webster]