No tail in the adult state: fore feet with four toes; hind feet with five, or with the rudiment of a sixth.
Skin smooth: hind feet very long, adapted for leaping; more or less palmated: upper jaw with a row of small fine teeth; also a transverse interrupted row on the middle of the palate.
Body swollen: skin warty; a porous protuberance behind the ears: hind feet of moderate length: jaws without teeth.
Body elongated; tail always present: fore feet with four toes; hind feet with five.
Tail compressed: jaws furnished with numerous small teeth; two longitudinal rows of similar teeth on the palate.