286 HISTORICAL PALEONTOLOGY. 



celebrated of the Cretaceous Deinosaurs is the Iguanodon, so 

 called from the curious resemblance of its teeth to those of the 

 existing but comparatively diminutive Iguana. The teeth (fig. 

 209) are soldered to the inner face of the jaw, instead of being 

 sunk in distinct sockets ; and they have the form of somewhat 

 flattened prisms, longitudinally ridged on the outer surface, 

 with an obtusely triangular crown, and having the enamel 

 crenated on one or both sides. They present the extraordinary 

 feature that the crowns became worn down flat by mastication, 

 showing that the Iguanodon employed its teeth in actually 

 chewing and triturating the vegetable matter on which it fed. 

 There can therefore be no doubt but that the Iguanodon, in 

 spite of its immense bulk, was an herbivorous Reptile, and 

 lived principally on the foliage of the Cretaceous forests 

 amongst which it dwelt. Its size has been variously estimated 

 at from thirty to fifty feet, the thigh-bone in large examples 



Fig. 209. Teeth of Iguanodon Mantellii. Wealden, Britain. 



measuring nearly five feet in length, with a circumference of 

 twenty-two inches in its smallest part. With the strong and 

 massive hind-limbs are associated comparatively weak and 

 small fore-limbs; and there seems little reason to doubt that 

 the Iguanodon must have walked temporarily or permanently 



