210 ANURA CHAP. 



The Cystignathidae may be said to represent the Ranidae in 

 Notogaea. Some of them can be distinguished from the true, 

 typical frogs solely by the arciferous type of the shoulder- 

 girdle and sternum. There is in both families the same adaptive 

 versatility, the same amplitude in the formation of the finger- 

 tips, the occasional slight dilatation of the sacral diapophyses, 

 the same range in the configuration of the omo- and meta-sternum. 

 In fact, young Ranidae, before the firmisternal character is assumed, 

 are indistinguishable from Cystignathidae, and the latter would 

 turn into Ranidae if they could be induced to consolidate their 

 sternal apparatus. 



The geographical distribution of the Cystignathidae is 

 suggestive of their being an old family, most of whose members 

 have reached a high stage of morphological development. The 

 overwhelming majority inhabit the Neotropical region, a few 

 forms extending into tropical Central America and into the 

 Antilles ; the rest, some twenty species only, are confined to the 

 Continent of Australia and to Tasmania. 



The family name is rather a misnomer. It is taken from the 

 genus Cystignathus, which is, or rather was, characterised by the 

 peculiarly broadened lower jaw, hollowed out by the vocal sacs ; 

 but this generic name had to give way to that of Leptodactylus, in 

 obedience to the often senseless rule of priority. The family 

 is composed of three sub-families. 



Sub-Fam. 1. Hemiphractinae. Teeth are carried by both 

 jaws, the voniers and the palatine bones ; or by the palatines and 

 parasphenoids in Amphodus. The vertebrae are opisthocoelous, 

 devoid of ribs, and the sacral diapophyses are not dilated. The 

 shoulder-girdle and sternum are strictly arciferous. The omo- 

 sternum is very much reduced ; the metasternum forms a 

 cartilaginous plate. The tongue is slightly free behind. The 

 tympanum is distinct. Three genera, with eight species, all 

 inhabitants of South America. 



J-femipkractus. The head is large ; the upper surface of all 

 the cranial bones appears pitted, owing to most of the covering 

 skin being involved in the ossification. The temporal fossa is 

 bridged over or roofed in by the fronto - parietal and the 

 squamosals, so that the orbit is completely encircled by bone, 

 as in Pelobates cultripes. The terminal phalanges are simple 

 and. are not dilated into discs. The teeth of the lower jaw are 



