( HAf. \ 



GEOGRAl'IlUAL 1 )1STKI lU'TION 



95 



there are not a tew resemblauces lietweeii tliis Eastern Asiatic 

 and the American t'anna. The I'rodela tliuslend no sni)])ort to the 

 usual division of the I'eriaretie into a Talaearetic and a Nearctic 

 sub-region. Xor is it possil)]e to divide the Palaearctic into a 

 Eurasian and a Mediterranean province. We have in this case 

 to distinguish between an American, an Asiatic, and a iMuopean 



: SALAM. LECHRIOOONTA 



.K 



S.MECODONTA. .'^^ ICHTHYODEA. 



Fig. 16. — Map .showing the distribution of the Urodela. " Iililliyode;i '" — -Aniiiliiuniidae 



-^ Froteidae + Sirenidae. 



fauna. The Asiatic or Eastern I'alaearctic sub-reuion assumes tlie 

 central position, at least from a merely geographical point of view. 

 It would be unjustifiable to assume a spreading from this centre 

 into Europe, and, on the other hand, into America. The centre 

 existed more prolmbly in the Arctic circle, now devoid of Urodela. 



So far as mere numbers of species are concerned the liuge 

 Asiatic or Eastern. Palaearctic region is the poorest, l)ut it is 

 also the least explored, and China will probably yield a good 

 many new forms. AVe know at present only 15 species, nearly 

 all from the eastern half These 15 species represent no less 

 than 11 genera, 8 of which (=73 per cent) are peculiar to the 

 sub-region. Xext comes the Western Palaearctic or European 

 sub-region with about '1 1 recent species of 5 genera, 4 of which 

 are peculiar. America is l)y far the richest, Avitli no less than 

 66 species (36 eastern, about 16 western, and the rest Central 

 American, etc.), belonging to 19 genera, 17 of which ( = 00 per 

 cent) are peculiar to the New World, liut this richness in species 

 is due mainly to the abundance of the two genera AmUi/stomd. and 

 Sjjchrpes, just as Europe is characterised ])y its many Tritons. 



One of the most striking features of the Asiatic sub-region is 



