THE LAND TORTOISES AND TERRAPINS 



2419 



nately octagonal and quadrangular, are irregularly hexagonal, with the shorter of 

 the two lateral surfaces placed posteriorly; since, however, the same feature occurs 

 in some of the true tortoises, it is not absolutely characteristic of the genus. 

 The areolated tortoise is a small species, with a shell of only four inches 

 in length. It is characterized by having only four claws on the front feet, and by 

 its depressed carapace, which is of equal width throughout, and has even margins. 

 On the back, the shields are more or less inflated, and separated from ofie another 

 by deep channels; the centre of each shield having a depressed areola, surrounded 





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DENTATED HINGED TORTOISES. 

 (One-fourth natural size.) 



by concentric grooves. In color, the carapace is olive, with a reddish-brown 

 centre to each shield; while the plastron is brown in the middle, and yellow at 

 the edges. A second species (H. femoralis) differs by having the hinder margin 

 of the shell serrated, and a conical tubercle on the hinder surface of the thigh; 

 while in a third (H. signatus) there are five toes on each fore-foot. Lastly, H. 

 nogueyi differs from all the others in its vaulted carapace, which is gibbose behind; 

 this species being from Senegal, while the other three are South African. In gen- 

 eral habits it is probable that the members of this genus closely resemble the true 

 tortoises. 



