amphineura

Century Dictionary and Cyclopedia

1. A class or phylum of Vermes constituted by the genera Neomenia and Chætoderma, together with the Chitonidæ, the latter being removed from the Mollusca and associated with the genera named on account of the similarity in the nervous system.
2. A class or order of marine Mollusca. They have a bilaterally symmetrical elongated body, with terminal month and anus; the shell either lacking or consisting cf 8 median pieces; mantle not divided into paired lobes; ctenidia absent or variously arranged; and the odontophore either present or lacking. The class includes the Chitonidæ, Neomeniidæ, and Chætodermatidæ.

GNU Webster's 1913

1. n. (Zoöl.) A division of Mollusca remarkable for the bilateral symmetry of the organs and the arrangement of the nerves.

WordNet 3.0

1. n. a class of Gastropoda