OF THE BATRACHIA. 113 



CAUDATA. 



Salamandridce. Number of Species. 



Salamandrirue. 

 Tylototriton* 1 



Amblystomatince. 

 Amblystoma 1 



APODA. 



Cceciliidce. 



Ichthyophis * 2 



Urseotyphlus 2 



Gegeneophis * 1 



5. The Tropical-American Region. 



The Tropical- American Region comprises the whole of South 

 America, Central America to the limits of the North-American 

 Region, and the West Indies. It exceeds every other Region with 

 regard to the number of families, genera, and species, the total 

 number of the latter being about four ninths of all those actually 

 known. 



The Ecaudata are represented by : — very numerous Cystignathidce 

 and Hylidce, these two families alone equalling in number all the 

 rest ; numerous Bufonidce and Engystomatidce ; few Ranidce, a few 

 of which only belong to the genus Rana ; the Dendrobatidce, the 

 second genus of which inhabits Madagascar ; the Dendrophryniscidce, 

 Amphignathodontidce, and Hemiphractidce, three small families con- 

 fined to this region ; and, finally, the Pipidce, which, with the African 

 Dactylethridce, constitute the suborder Aglossa. 



A small number of Caudata, belonging to the genus Spelerpes, 

 inhabit Central America — two species, favoured by altitude, extend- 

 ing southwards to Colombia, and a third reaching a few degrees 

 south of the equator. A species of the same genus has also been 

 recently described from the West Indies. But the most extraordi- 

 nary instance of geographical distribution, if it be confirmed, will 

 be the presence in the valley of the Plate river of a species of 

 Plethodon extremely closely allied to the Calif ornian forms. 



The Apoda are represented by 6 genera and 21 species. Out of 

 these 6 genera, 5 are peculiar to the region ; the other, curiously 

 enough, it has in common with West Africa. 



The striking character of this region is the great proportion 

 (224 : 38) of Arcifera, and especially of Cystignathidce and Hylidce, it 

 in this respect resembling the Australian region. Its affinities with 

 the Indian and African regions are shown by the development of 

 Engystomatidce, and with the latter region particularly by the pre- 

 sence of Aglossa, Dendrobatidce, and the Apodal genus Dermophis. 

 As to its affinities with the North-American region, it is well 

 known that one fauna passes gradually into the other; but if we 

 compare the fauna of the United States with that of South America, 

 the difference between them is as great as between those of any 

 other two Regions, Africa and Australia excepted. 



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