52 



GUIDE TO REPTILES AND AMPHIBIANS. 



Case 



the upper jaw. The Painted Terrapin (Chrysemys pida, 86, fig- 52) 

 typifies another North American genus, most of the members of which 

 are distinguished by their bright colouring and the elaborate patterns 

 on the shell especially when young. Ocadia (101) is now exclusively 

 Chinese, although fossil species occur in the Tertiary rocks of Europe. 

 Bellia (102, 103) and Damonia (105-108) are Indian, the former 

 easily recognised by the balloon-shaped vertical shields of the cara- 

 pace. Another Indian genus is Geoemyda (127-130), the members 

 of which are to a great extent terrestrial, and thus indicate a transi- 

 tion towards those species of land Tortoises, like Testudo emys (172), 

 in which the shell is flatter than usual. 



A group of aquatic Oriental Tortoises, for the most part of large 

 size, are (from the Indian name of the typical species) collectively 

 designated Batagurs. They include the genera Kachuga (96-99), 



Fig. 53. 



Carapace of the Thurgi Batagur (Hardella thurgi), with the horny shields 

 removed ; much reduced in size. The wavy lines show the divisions (or 

 sutures) between the bones; the firm lines indicate those between the 

 overlying horny shields, c. 1-8, costal bones ; m. 1-11, marginal bones ; 

 n. 1-8, neural bones ; mi. nuchal bone ; py. pygal bone ; spy. 1, 2, supra- 

 pygal bones. (No. 131-) Note that the horny plates do not correspond 

 with the bony ones. 



