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CLASS REPTILIA. 



without sufficient foundation, that it indicates a form allied to 

 Ccelurus. 



Order IX. Crocodilia. — The Crocodiles of the present day 

 are well-known, lacertiform Reptiles inhabiting the lakes, rivers, 

 and marshes of the warmer regions of the globe ; and are the 

 largest existing representatives of the entire class. If we had only 

 these existing and specialised forms to deal with, we should have 

 no difficulty in giving a concise definition which would separate the 

 order to which they belong from the Dinosauria. There occur, 

 however, in the Trias a number of generalised forms which ap- 

 proximate so closely to the latter order as to render such definition 

 extremely difficult ; and it is quite possible that some of the under- 

 mentioned characters are not applicable to the first suborder. The 

 order is sometimes known as the Emydosauria. 



In all the forms the limbs and body (fig. 1079) are of a lacerti- 

 form type, the former being very short, and the latter long and 



Fig. 1079. — Head and fore-part of the body (a) and hind foot (b) of Crocodilus porosus , 

 from Madras. Much reduced. (After Gunther.) 



carried close to the ground ; while the tail is relatively long. With 

 the exception of a few later Jurassic forms, the dorsal aspect of the 

 body carries a dermal armour of articulating or imbricating bony 

 scutes, arranged in two or more longitudinal rows (fig. 1079), and 

 marked on their outer surface by a series of deep pits. In certain 

 cases there may also be an armour of similar type developed on the 

 ventral surface of the body. The centra of the vertebrae are either 

 amphi- or proccelous, and the neuro-central suture is persistent. 



