378 



REPTILIA. 



The teeth of Iguanodon (fig. 326) present a singularly close 

 resemblance in shape to those of the comparatively pigmy 

 Iguanas of the present day. Their crown is obtusely sub-tri- 

 angular, with longitudinal ridges, and having the surface of the 



Fig. 326. Teeth of Iguanodon Mantellii. Wealden. 



enamel crenated on one or both sides. They present the ex- 

 traordinary feature that the crown became worn down flat by 

 mastication, showing that Iguanodon employed the teeth in the 

 actual trituration of the vegetable matter on which it fed. 



The gigantic Cetiosaurus of the Oolitic and Cretaceous 

 Rocks was originally placed amongst the Crocodilia; but the 

 researches of Professor Phillips have shown that it belongs 

 really to the Deinosauria. Having obtained a magnificent 

 series of remains of this reptile, Professor Phillips has been 

 able to determine many very interesting points as to the 

 anatomy and habits of this colossal animal, the total length 

 of which he estimates as being probably not less than sixty 

 or seventy feet. As to its mode of life, this accomplished 

 writer remarks : 



" Probably when ' standing at ease ' not less than ten feet in 

 height, and of a bulk in proportion, this creature was un- 

 matched in magnitude and physical strength by any of the 

 largest inhabitants of the Mesozoic land or sea. Did it live in 

 the sea, in fresh waters, or on the land ? This question can- 

 not be answered, as in the case of Ichthyosaurus, by appeal to 

 the accompanying organic remains ; for some of the bones lie 



