Species of North American Tortoises. 127 



easily walk with a weight of sixty pounds on its back. Its 

 food consists of fruit, insects, and the edible fungi, particularly 

 the different species of clavaria. Many persons are in ths 

 habit of keeping them in their cellars, where they destroy 

 snails, crickets, and other noxious insects ; it may however be 

 questioned whether they ever attempt, as has been said, to 

 devour rats and mice ; they are not well formed for the pur- 

 suit of such active animals, who have too much sense to suffer 

 themselves to be caught by so sluggish a hunter. The same 

 may be said of the ridiculous stories of their catching and de- 

 stroying snakes. This species has been cited as an example 

 of longevity among animals of the lower classes : all tortoises 

 are long-lived ; but the finding of an individual with a name 

 and date engraven on its sternum proves nothing : the idle and 

 the foolish are fond of inscribing their names every where, 

 and may as well antedate the time by half a century, as state 

 the true year of their attempts at immortality. 



16. Testudo serpentina. 



Testa ovalis, plus minus carinata, postice utrinque tridentata : 

 sternum parvum, angustum, rhombiforme : caput magnum, 

 mandibula superiore hamata ; cauda magna, longa, cristata. 



Chelonura serpentina, Say, loco cit. Emi/s serpentina, 

 Merrem. Serrated tortoise, Pennant Arct. Zool. Supp. No. 6. 

 Alligator tarapin of the southern states ; loggerhead or snap- 

 ping turtle of the northern. 



Shell oval, rather depressed, more or less carinate, emargi- 

 nate behind, above dusky or dark cinereous. First vertebral 

 plate pentagonal, wider in front, the lateral faces rounded, the 



Vox,. Ill 17 



