_Amphignathodon_, of which only one species is known, _A. guentheri_ of Ecuador, agrees with _Nototrema_ in all important characters except that it possesses teeth in the lower jaw in addition to those in the upper. There are further differences, but they are of degree only. The sacral diapophyses are more strongly dilated and the omosternum is absent. The tympanum is distinct. The pupil is horizontal; the roundish tongue is slightly free behind. The terminal phalanges are claw-shaped and carry large discs. The female has a dorsal pouch opening backwards. The skin of the head is involved in the ossification of the cranial bones. The skin of the back is smooth, slightly tubercular, non-granular below. The middle of the upper eyelid carries a small, pointed, cutaneous appendage, and even this little character occurs also in some species of _Nototrema_, _e.g._ in _N. longipes_ and in _N. cornutum_. The heel carries a triangular little flap. The upper parts are olive in spirit-specimens, probably green in life; the borders of the dorsal pouch {189}are black. The sides of the body are adorned with a black, white-edged streak, the limbs are whitish, with black cross-bars. The total length of the female type-specimen is 3 inches. SUB-FAM. 2. HYLINAE.–_Lower jaw toothless._ The Hylinae are divided by Boulenger into 13 genera, which can be recognised by the following key, without reference to their natural affinities:– _A._ The contracted pupil forms a horizontal slit. _a._ Tips of the fingers and toes with large discs, α. With vomerine teeth. Female without a dorsal pouch .......... _Hyla_, p. 189. Female with a dorsal pouch .......... _Nototrema_, p. 202. β. Without vomerine teeth .......... _Hylella_, p. 203. γ. With parasphenoid teeth and peculiar helmet-shaped head. Yucatan .......... _Triprion_, p. 207. Ecuador and Mexico .......... _Diaglena_, p. 207. _b._ Tips with very small discs. Tongue free behind. Tympanum distinct. North America and Peru .......... _Chorophilus_, p. 208. Tympanum indistinct. North America .......... _Acris gryllus_, p. 207. _c._ Tips simply swollen, not dilated into discs. Brazil .......... _Thoropa miliaris_, p. 209. _B._ The contracted pupil forms a vertical slit. Tropical America. _a._ Tips with large discs. α. Tongue extensively free behind. Inner finger and toe opposable .......... _Phyllomedusa_, p. 203. Inner finger and toe not opposable .......... _Agalychnis_, p. 206. β. Tongue scarcely free behind. Ecuador .......... _Nyctimantis rugiceps_, p. 206. _b._ Tips without discs. Without parasphenoid teeth, but head peculiar in shape. Mexico .......... _Pternohyla fodiens_, p. 207. _C._ Pupil rhomboid. Without parasphenoid teeth. Large discs. Head helmet-shaped. Brazil .......... _Corythomantis greeningi_, p. 207.