214 P1CTURUESQE SKETCHES 



with a scaly armour, the plates heing oval or circular, 

 and therefore not fitting one another, but studded in 

 unconnected order over the surface of a tough skin. 

 It has been supposed, by Dr. Mantell, that certain 

 broad bones found with the skeleton formed a fringe 

 on the back of the animal, but Professor Owen has 

 suggested that they may, with greater probability, be 

 ribs which defended the abdomen, analogous to a cor- 

 responding contrivance in the Ornithorhynchus. 



Reverting now to the Megalosaurus, which, in some 

 of the important characters I have referred to, is nearly 

 allied to the Iguanodon and Hyl&osaurus, it appears 

 that these three form a natural and well-marked 

 group of reptiles now entirely extinct, combining a 

 complicated method of implanting the teeth in sockets, 

 with limbs of gigantic size and strength, sustaining 

 a bulky trunk by a long arched sacrum firmly ce- 

 mented into a bony ridge. These modifications of 

 structure, the most perfect yet discovered in reptiles, 

 are found in animals which attained colossal dimen- 

 sions, and must have played a conspicuous part during 

 the middle secondary period, as well in the character 

 of carnivorous as herbivorous animals. They seem, 

 indeed, to have been the most important members 

 this earth has ever witnessed of that great natural 

 class of cold-blooded oviparous animals which we call 

 reptiles.* 



And these animals were by no means rare during 

 their period of existence, for, with regard to the 

 Iguanodon alone, fragments of not less than seventy 

 individuals appear to have come under the inspection 

 of one person (Dr. Mantell) within a few years, all 



* Owen's " Report," ante cit. p. 200. 



