408 GEOGRAPHICAL ZOOLOGY. ' [part iv. 



Neotropical aud Oriental regions ; in the Ethiopian there is a 

 considerable diminution in the number of species, and in the 

 Palaearctic they are still less numerous, being confined to the 

 warmer parts of it, except one species which extends as far north 

 as Hungary and Prussia. The genera are : — 



Testudo (25 sp.), most abundant in the Ethiopian region, 

 but also extending over the Oriental region, into South 

 Europe, and the Eastern States of North America ; Emys 

 (64 sp.), abundant in North America and over the whole 

 Oriental region, less so in tlie Neotropical and the Palaearctic 

 regions ; Cinosternon (13 sp.). United States and California, 

 and Tropical America; Aromochelys (4 sp.), confined to the 

 Eastern States of North America ; Staurotyims (2 sp.), Guate- 

 mala and Mexico ; Chclydra (1 sp.), Canada to Louisiana ; 

 Claudius (1 sp.), Mexico ; Dcrmatemys (3 sp.), South America, 

 Guatemala, and Yucatan ; Terrapene (4 sp.), Maine to Mexico, 

 Sumatra to New Guinea, Shanghae and Formosa — a doubtfully 

 natural group ; Cmyxis (3 sp.), Pyxis (1 sp.), Chersina (4 sp.), 

 are all Ethiopian ; JDumerilia (1 sp.), is from Madagascar only. 



Family 58.— CHELYDID^. (10 Genera, 44 Species.) 



General Distribution. 



The Chelydidpe, or fresh-water tortoises with imperfectly 

 retractile heads, have a remarkable distribution in the three 

 great southern continents of Africa, Australia, and South 

 America ; the largest number of species being found in the latter 

 country. The genera are : — 



Peltocephalus (1 sp.), Podocnemis (6 sp.), Hydromedusa (4 sp.), 

 Chelijs (1 sp.), and Platemys (16 sp.), inhabiting South America 

 from the Orinooko to the La Plata, the latter genus occurring 

 also in Australia and New Guinea ; Chclodina (5 sp.), Chelcmys 

 (1 sp.), and Elseya (2 sp.) from Australia ; while Sternotheres 



