306 GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION. 



The coecilians are tropical forms belonging to the East Indies, 

 Africa (with the Seychelles Hypogeophis rostratus), and America. 

 The American species, including all of the genus Coscilia itself, are 

 about twenty in number, and range from Mexico to Peru and 

 Brazil.* Kemarkable instances of divided genera are presented by 

 Dermophis, which possesses five American species and one from 

 West Africa (D. Thomensis), and Urseotyphlus, represented by two 

 species in Malabar and likewise one in West Africa. 



The urodele amphibians are comprised in four families : The 

 Sirenidse or sirens, with two or three species, inhabiting the South- 

 eastern United States ; the ProteidaB, with two genera, Proteus and 

 Menobranchus (or Necturus), the former confined to the subter- 

 ranean waters of Carinthia, Carniola, and Dalmatia, and the latter 

 to the streams of Eastern and Central United States and Canada; 

 the Amphiumidae, with three genera, two of which, Amphiuma and 

 Menopoma, represent North American forms, while the third, Sie- 

 boldia (Cryptobranchus or Megalobatrachus), which is closely re- 

 lated to the menopomas, is confined to Japan and China ; and the 

 Salamandridae (newts, salamanders, &c.), comprising upwards of 

 ninety species, very extensively distributed throughout temperate 

 Eurasia and North America, with some fifteen or more species in 

 tropical America (from Mexico southward Amblystoma, Spelerpes), 

 a limited number in North Africa, and two (Tylotriton) in the 

 Himalayas. The North American forms belong principally to the 

 genera Plethodon, Desmognathus, Diemyctylus, Amblystoma (with 

 Axolotl), and Spelerpes, the first two of which appear to be restricted 

 to the Western Hemisphere.! Spelerpes has one species (S. fuscus) 

 in the south of Europe, and Amblystoma one (A. persimile) in 

 Siam, remarkable instances of separation in genera. The urodele 

 Amphibia of North America, north of the Mexican boundary, num- 

 ber about fifty species. The permanent larval forms of one or more 

 species of Amblystoma (A. tigrinum, A. mavortium), known as 



* Boulenger gives the range of Chthonerpeton indistinctum as extending 

 to Buenos Ayres ; but this is considered doubtful by Peters (" Monatsb. Berl. 

 Akad.," 1879, p. 940). 



t American zoologists recognise the Plethodontidse (with Spelerpes), Des- 

 mognathidse, and Amblystomidee as distinct families ; Diemyctylus, repre- 

 senting the Pleurodelidse, is by Boulenger considered to be synonymous with 

 the Eurasiatic Molge (Triton of Laurenti). 



