{213}_A._ Pupil contracted into a horizontal slit. _a._ Omosternum rudimentary. Vomerine teeth present. α. Tympanum distinct .......... _Phanerotis fletcheri._ β. Tympanum hidden .......... _Cryptotis brevis._ _b._ Omosternum present. Vomerine teeth vestigial. .......... _Crinia_, 4 species. _c._ First finger opposed to the others .......... _Chiroleptes_, p. 221. _B._ Pupil contracted into a vertical slit. _a._ Omosternum rudimentary. Vomerine teeth absent. .......... _Hyperolia marmorata._ _b._ Omosternum fully developed. Vomerine teeth present. α. Tympanum distinct. Toes webbed. .......... _Mixophyes fasciolatus._ β. Tympanum hidden. Toes webbed. .......... _Heleioporus_, p. 222. γ. Tympanum indistinct. Toes free or slightly webbed. .......... _Limnodynastes_, p. 222. _Pseudis_, widely distributed over South America, consists of four species which have the appearance of long-legged frogs. The fingers, of which the first is opposed to the others, are free; the long toes are fully webbed. The tympanum is exposed. _P. paradoxa_ is absolutely aquatic, floating in pools, and is extremely shy. In life it is most beautifully coloured with bronze, bright green, and black markings above; underneath it is shiny yellow, with brown spots on the body and stripes on the thighs. Within a few minutes after death all the brilliant colours of the smooth skin of the back turn into dull uniform brown, with indistinct darker spots. Total length of the adult from 2 to 2½ inches. The specific name refers to the peculiar shape and monstrous size of the larva or tadpole.