VI 



RANIDAE^ANINAE 



239 



of horny sheaths, it is the hone itself which is thus shiirpened 

 and perforates the skin, an anomaly reminding us of the ribs 

 of Triton walfli. Total length of the type -specimens, about 

 3 inches. 



Adhesive discs are common, and are best developed in Elmvo- 

 jiJiorns, Ixalus, Rappia, and Megalixalus. In the Neotropical 

 genera, excepting Colosthetus, the discs are very peculiar, l)eing 

 provided on the upper side with leathery scales which are 

 separated by a fissure. The fourth and fifth metatarsals either 

 diverge and are connected by a distinct web, or they lie close 



= RAMinAF illlllll DENDROBATES. W//.FOPMS WITH FINGER DISCS. 



Fig. 4t). — Map .showing distribution ot the Ranidae. 



together with only a groove between them, or lastly they appear 

 externally united. 



The tympanic disc is very variable, large, small or (piitc 

 hidden. Vomerine teeth are present or absent. The pupil con- 

 tracts into a horizontal slit except in some Palaeotropical genera. 

 The tongue is universally free behind, mostly deeply notched, 

 and can be well protruded ; only in the Indian Oxyglossvs and 

 in the Neotropical genera, excepting Hylixalus, its posterior 

 margin is entire. — There are terrestrial, arboreal, and aquatic 

 members in this large sub-family. The geographical distril)ution 

 of the Eaninae, which comprise about twenty genera with at least 

 some. 270 species, is almost entirely Ai'Ctogaean. None, witli 

 the exception of three species in tlie Papuan subregion, occur 

 in the Australian region ; and only four genera, with one or 

 two species each, inhabit tlie tropical Aiidesian district, the 



