DEINOSAURIA. 379 



in marine deposits, others in situations marked by estuarine 

 conditions, and, out of the Oxfordshire district, in Sussex, in 

 fluviatile accumulations. Was it fitted to live exclusively in 

 water ? Such an idea was at one time entertained, in conse- 

 quence of the biconcave character of the caudal vertebrae, and 

 it is often suggested by the mere magnitude of the creature, 

 which would seem to have an easier life while floating in water, 

 than when painfully lifting its huge bulk, and moving with slow 

 steps along the ground. But neither of these arguments is 

 valid. The ancient earth was trodden by larger quadrupeds 

 than our elephant ; and the biconcave character of vertebrae, 

 which is not uniform along the column in Cetiosaurus, is perhaps 

 as much a character of a geological period as of a mechanical 

 function of life. Good evidence of continual life in water is 

 yielded in the case of Ichthyosaurus, and other Enaliosaurs, 

 by the articulating surfaces of their limb-bones, for these, all of 

 them, to the last phalanx, have that slight and indefinite adjust- 

 ment of 'the bones, with much intervening cartilage, which fits 

 the leg to be both a flexible and forcible instrument of nata- 

 tion, much superior to the ordinary oar-blade of the boatman. 

 On the contrary, in Cetiosaur, as well as in Megalosaur and 

 Iguanodon, all the articulations are definite, and made so as 

 to correspond to determinate movements in particular direc- 

 tions, and these are such as to be suited for walking. In par- 

 ticular, the femur, by its head projecting freely from the ace- 

 tabulum, seems to claim a movement of free stepping more 

 parallel to the line of the body, and more approaching to the 

 vertical than the sprawling gait of the crocodile. The large 

 claws concur in this indication of terrestrial habits. But, on 

 the other hand, these characters are not contrary to the belief 

 that the animal may have been amphibious ; and the great 

 vertical height of the anterior part of the tail seems to support 

 this explanation, but it does not go further. For the later 

 caudal vertebrae, instead of being much compressed, as in 

 Teleosaurus, are nearly circular in the cross section, and are 

 interlocked by posterior zygapophyses, extended over half or 

 the whole length of a vertebrae. We have therefore a marsh- 

 loving or river-side animal, dwelling amidst filicine, cycadace- 

 ous, and coniferous shrubs and trees full of insects and small 

 mammalia. What was its usual diet? If ex ungue leonem, 

 surely ex dentedbum. We have indeed but one tooth, and that 

 small and incomplete. It resembles more the tooth of Iguan- 

 odon than that of any other reptile ; for this reason it seems 

 probable that the animal was nourished by similar vegetable 

 food which abounded in the vicinity, and was not obliged to 



