gnathostoma

from The Century Dictionary.

• noun A genus of nematoid entozoic worms, found in the stomach of the Felidœ or cat tribe. R. Owen. See Chiracanthus, 2.

from the GNU version of the Collaborative International Dictionary of English.

• noun plural (Zoöl.) A comprehensive division of vertebrates, including all that have distinct jaws, in contrast with the leptocardians and marsipobranchs (Cyclostoma), which lack them.