of an almost pel feet Skeleton of the Plesiosaurus. 4 13 



witli regard to the other parts of the skeleton, in assigning to 

 the same animal the heads and vertebrae, which had at that 

 time never been fbuiul in connexion, and whose actual relation 

 was therefore regarded by many as equivocal, in indicating the 

 order and place of the several kinds of vertebree, and in tracing 

 the osteology of {he humero-sternal parts, my opinions have 

 received full confirmation. In the attempted restoration of the 

 paddle also (though professedly given only on conjecture) a 

 very considerable approximation to the true structure of the 

 part will be found, considenng the very imperfect materials 

 afforded by the fragments which had then been obtained. 



But in addition to these particulars, which in all their ma- 

 terial features were correctl}' stated, the specimen now exhi- 

 bited presents others of a most novel and interesting charac- 

 ter, not to have been anticipated previously to the discovery of 

 a skeleton, the whole exterior portion of whose vertebral co- 

 lumn was ]3erfect. 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 vertebras 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 interesting feature of the re- 

 cent 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 of this part only, 

 in possession of MissPhilpot, confirm the restoration attempted 

 from the distorted head figured in Plate XIX. of the first, 

 volume of the second series of the Geological 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 orie-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. 



Vcrtcbrcc. — The distinctions between the cervical and cau- 

 dal vertebra; have been fully and correctly stated in my 

 former communications; but I had not at that time observed 

 more than tw( Ive of the cervical, whereas tlie present speci- 

 men exhibits about tliirtv-five, or, includir)g the anterior dor- 



