2452 



TORTOISES, TURTLES, AND PLESIOSAURS 



thirty inches in length. It belongs to a genus including seven existing species, of 

 which six are South American, while the seventh is an inhabitant of Madagascar. 

 This extremely anomalous distribution is to some extent explained by the oc- 

 currence of a fossil representative of the genus in the Eocene strata of India, 

 which probably indicates that these tortoises were at one time widely spread. As 

 a genus, these tortoises are characterized by the skull having a roof over its 

 temporal region, coupled with the presence of five claws on the fore-feet, and four 

 on the hinder pair, and likewise by the circumstance that the mesoplastral bones 

 are small and confined to the edges of the plastron, so that they are widely 



GIANT AMAZONIAN TORTOISE. 

 (One-sixth natural size.) 



separated from one another in the middle line. The toes are broadly webbed, 

 and the tail is remarkable for its extreme shortness. 



The figured species, which inhabits tropical South America to the eastward of 

 the Andes, and is extremely abundant in the upper part of the Amazonian system, 

 has the shell expanded posteriorly, and much depressed in the adult, although at 

 an earlier stage it has a roof-like form. The chin is furnished with two small 

 wart-like appendages, and the hind-foot characterized by the presence of two very 

 large shields on its outer side. In color, the upper shell is brown cr olive, with 

 darker markings, while the plastron is yellowish, spotted with brown; the young 



