382 The Rev. W. D. Conybeare on the Discovery of 



conjecture)^ a very considerable approximation to the true structure of the 

 part will be found, considering the very imperfect materials afforded by the 

 fragments which had then been obtained. 



But in addition to these particulars, which in all their material features 

 were correctly stated, the specimen now exhibited presents others of a most 

 novel and interesting character, not to have been anticipated previously to the 

 discovery of a skeleton the whole exterior portion of whose vertebral column 

 was perfect. I particularly allude to the neck, which is fully equal in length 

 to the body and tail united; and which surpassing in the number of its vertebrae 

 that of the longest-necked birds, even the swan, deviates from the laws which 

 were heretofore regarded as universal in quadrupedal animals, and the cetacea. 

 I mention this circumstance thus early, as forming the most prominent and in- 

 teresting feature of the recent discovery, and that which in effect renders this 

 animal one of the most curious and important additions which geology has yet 

 made to comparative anatomy. 



I now proceed to the details in the usual order. 



Head. — The present specimen, and another bf this part only, in possession 

 of Miss Philpot, confirm the restoration attempted from the distorted head 

 figured in Plate XIX. of the first volume of the second series of the Geologi- 

 cal Transactions ; and the latter extends our knowledge by exhibiting distinctly 

 the occipital portion. We now also learn for the first time, that the head of 

 this animal was remarkably small, forming less than the thirteenth part of the 

 total length of the skeleton ; while in the Ichthyosaurus its proportion is one- 

 fourth. This proportional smallness of the head, and therefore of the teeth, 

 must have rendered it a very unequal combatant against the latter animal ; 

 but the structure of its neck may perhaps be considered as a compensating 

 provision, supplying it with the means of security and of catching its prey. 



Vertehrce. — The distinctions between the cervical and caudal vertebrae 

 have been fully and correctly stated in my former communications ; but I had 

 not at that time observed more than twelve of the cervical, whereas the present 

 specimen exhibits about thirty-five, or, including the anterior dorsal, which 

 were placed before the humerus and bore only five ribs, forty-one*. This 

 great increase of the number of joints in the neck, is the more remarkable 

 fiom the rigour with which nature appears, in most cases, to have enforced 

 the law of a very limited number. In all quadrupedal animals, in all the 



* It is difficult to assign the exact demarcation between these subdivisions of the column ; 

 because the inferior lateral or hatchet-shaped processes of the cervical vertebrae (which in this 

 animal greatly resemble those of the crocodile) gradually become elongated, and assume almost 

 insensibly the character of false ribs. 



