193 Sir P. G. Egerton, Bart, on certain peculiarities in the 



saurus, is compatible with the ideas we may have formed of the exigencies of 

 the animal^ from our previous knowledge of its structure and habits. It has 

 been established, upon evidence the most conclusive, that the Ichthyosaurus 

 was a carnivorous reptile, inhabiting the sea, and breathing air, and the more 

 we study its organization the more we see the beautiful adaptation of all its 

 parts to such a mode of life. The lengthened snout, capacious jaws, and 

 prehensile teeth, enabled it to seize and retain its slippery prey; while the 

 broad expanse of tail, and the fish-shaped vertebrae, afforded a powerful appa- 

 ratus for progression through the fluid that it is supposed to have inhabited, in 

 pursuit of the finny tribes, which, principally, constituted its food. This com- 

 bination of organs of pursuit and prehension for the capture of its prey, would 

 have been of little avail, without the power of control and direction ; conse- 

 quently we find in the thoracic region, a powerful apparatus connected with 

 the anterior extremities, to regulate and govern the movements of the body. 



Mr, Conybeare, speaking of this structure, says*=, " The form of the sternal 

 arch, and the broad surfaces of the clavicles is such as to impart great strength 

 to the chest, enabling the animal to breast the most disturbed waters, and 

 affording an extensive surface for the attachment of powerful muscles to assist 

 in moving the anterior extremities." It was further necessary that the head, 

 constituting one-fourth of the entire length of the animal, should be furnished 

 with adequate powers to enable it, not only to cleave the waves with steadiness 

 and ease, but to obey each impulse, in directing the pursuit, with quickness 

 and precision. If we examine living structures, we find in the whale, a 

 fulcrum for the support of the ponderous head in the anchylosis of the cervical 

 vertebra;. In fishes we find provisions for rapid progression in the con- 

 struction of the spinal column. The Ichthyosaurus required a combination 

 of the two powers; and as former observers'!" have demonstrated most clearly 

 the beautiful adaptation of the animal's organization for progression through 

 the waters, so I trust I may no less clearly have established, by the foregoing 

 details, the existence of contrivances in the cervical vertebrae, fully sufficient 

 to have afforded that enlarged amount of power, which the habits of the 

 animal, and the proportions and arrangement of its parts would seem to 

 suggest to have been almost necessary to its existence. Doctor Buckland, 

 when speaking of the "Ossemens Fossiles," and of the author of that work, in 

 his Bridgewater Treatise, says| " Nothing can exceed the accuracy of the 



* Geol. Trans. 1st Series, vol. v. p. 578. 



t Geol. Trans. 1st Series, vol. v. p. 559 et seq. 2nd Series, vol. i. p. 103 et seq. 



X Vol. i. p. 140. 



