TURTLES AND TORTOISES 35 



a temptation to place them in a family by themselves. 

 This step would be necessary if a few of the preceding 

 genera were unknown. As matters stand, a technical 

 arrangement of the chelonians shows us, step by step, the 

 relationship of the high-shelled tortoise of the deserts 

 to the depressed, persistently aquatic turtle with its 

 broadly webbed feet. 



The True Tortoises: True tortoises are embraced 

 within four genera. These are Cinixys, Pyxis, Homo- 

 pus and Testudo. The latter is the most extensive 

 genus, containing about forty-five species ; Ciniooys con- 

 tains three species ; Pyxis is represented by a single tor- 

 toise and Homopus by four species. 



To these mostly slow-moving and — in the human eye 

 — ungainly creatures, we must award the standard for 

 the highest degree of intelligence among reptiles. Tor- 

 toises appear to exhibit reasoning powers equal to the 

 warm-blooded animals. Their wanderings are often ex- 

 tensive, but they are not vagrant prowlers like the 

 greater number of snakes and lizards. They have a 

 dwelling place — a burrow, or hollowed-out spot among 

 rocks or bushes ; to this they return after their explora- 

 tions with a regularity rivaling the "instinct" of the fox 

 and other den-dwelling mammals. Some tortoises in- 

 habit desert areas under a sun almost unendurable to the 

 human; these desert species live in long burrows from 

 which they prowl by night or during the dawn to clusters 

 of cacti and other sparse vegetation of such regions, 

 where they browse. All tortoises inhabit areas that are 

 at least comparatively dry. Many are so grotesquely 

 marked as to suggest weird coffers that might hold the 

 jewels of some princess of the past. New World species 

 are few. Africa is the home of the greater number. 



Genus Cinixys; the Hinge-Backed Tortoises: Trop- 



