'Gnathostoma' definitions:

Definition of 'Gnathostoma'

From: GCIDE

Gnathostoma \Gna*thos"to*ma\, n. pl. [NL., from Gr. gna`qos the jaw + ?, ?, the mouth.] (Zool.) A comprehensive division of vertebrates, including all that have distinct jaws, in contrast with the leptocardians and marsipobranchs (Cyclostoma), which lack them. [Written also Gnathostomata.]