TORTOISES AND TERRAPINS. 49 



carapace, but with a hinge in the plastron. It does not exceed four 

 inches in length. 



The typical Laud Tortoises included in the genera Testuclo Case 7. 

 (147-176) and Homopus (144, 145) are characterised by their 

 vaulted shells, in which the plastron is normally without a hinge 

 and firmly united by a strong bridge to the carapace. The feet, 

 of which the hind-pair are clnb-shaped, are not webbed, and have 

 not more than two joints to each toe. On the front of the 

 fore-limbs the skin carries stout horny shields, sometimes under- 

 lain by bony nodules, and large shields cover the head. The tail 

 is short. Usually the neural bones of the carapace are alternately 

 quadrangular and octagonal, but they may be hexagonal, with the 

 shorter lateral surfaces posterior ; the costals are alternately wide 

 and narrow at the ends. Generally the supracaudal shield is single. 

 Tortoises of the genus Testado range throughout the warmer parts 

 of the world except Australasia and some of the Malay Islands. 



The majority of existing Land Tortoises are of small or medium 

 size, but a number of island species attained much larger dimensions. 



Within historic times the distribution of species of Testudo large Case 7 and 

 enough to be called gigantic has been restricted to two areas. These table- 611 * 

 are the Galapagos (Tortoise) Islands, on the Equator off the west cases, 

 coast of South America, and certain islands on the western side of 



Fig. 51. 



The Abingdon Island Saddle-backed Tortoise {Testudo abingdoni), remarkable 



for the thinness of its shell, from the Galapagos group. (No. 153) 



From a specimen in the Museum. 



the Indian Ocean, including the Mascarenhas (Reunion, Mauritius, 

 and Rodriguez), the Aldabra group, the Amirantes, and the 



E 



