LARGE TORTOISES 



It is to be noticed, however, that the skin skeleton 

 of the tortoise tribe is not absolutely sui generis. In 

 detail, of course, nothing like it is found in any other 

 reptile at present known. But the dorsal part of the 

 box or carapace is, of course, to be compared with 

 the dorsal bony skin shields of crocodiles, while the 

 same comparison holds good with regard to the ventral 

 plastron, which is, moreover, comparable to the thin 

 ossifications found on the ventral surface of Hatteria, 

 and in that reptile termed abdominal ribs. Toothless- 

 ness happens not to be an attribute of any living group 

 of reptiles except the Chelonia ; but there are extinct 

 families, though not orders, which are in the same 

 way without teeth. Here, as elsewhere in Nature, 

 hard and fast lines of demarcation do not exist. The 

 selection of tortoises at the Zoo is a considerable one 

 at any time. 



TESTUDO DAUDINI 



This tortoise is actually the largest living repre- 

 sentative of the giant tortoises of the world. Large 

 tortoises do not differ from small ones, such as the 

 Testudo grceca of southern Europe, and of our streets 

 in London at certain times. That is to say, they are 

 anatomically not separable, though vastly exceeding 

 them in size, and also characterized by a varying 

 number of small external and other features, which 

 allow us to place the large tortoises in several species. 

 At present we only find very large tortoises on small 

 islands. It is hardly an exaggeration to say that the 

 smaller the island the larger are its tortoises. This is 

 very unexpected, because, among the mammalia at 

 any rate, beasts seem to require a spacious environ- 

 ment to attain to any bulk. Madagascar, for example, 

 has small mammals, while in the forests of the neigh- 



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