any small marine gastropod mollusc of the group or order Pteropoda, in which the foot is expanded into two winglike lobes for swimming and the shell is absent or thin-walled
Also called: sea butterfly
pteropod in American English
(ˈtɛrəˌpɑd)
adjective
1.
of or relating to certain orders of small, thin-shelled or shell-less gastropod mollusksthat swim by means of winglike lobes on the foot