RANIDAE ANINAE 



239 



of horny sheaths, it is the bone itself which is thus sharpened 

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

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

 3 inches. 



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

 phorus, Ixalus, Rappia, and Afegalixalus. In the Neotropical 

 genera, excepting Colosthetus, the discs are very peculiar, being 

 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 



^= RANIDAE. Illlllll DENDROBATES. W///. FORMS WITH FINGER DISCS. 



FIG. 46. Map showing distribution of the Ranidae. 



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

 externally united. 



The tympanic disc is very variable, large, small or quite 

 hidden. Yomerine 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 Oxyglossus 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 distribution 

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

 some 270 species, is almost entirely Arctogaean. None, with 

 the exception of three species in the Papuan subregion, occur 

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

 two species each, inhabit the tropical Audesian district, the 



