♦so Rev. W. D. Conybeare on the Skeleton of the Plesiosaurus. 



tended this part, viz. natation, being the same, a similar modi- 

 fication has been superinduced on the usual structure ot" qua- 

 drupedal extremities. 



On the whole, this part in the Plesiosaurus presents a link 

 between the usual structure and the still more complicated or- 

 ganization of the paddle in the Ichthijosaunis ; the phalanges 

 are flattened as in the turtle, and other animals destined for 

 natation, and were doubtless in like manner covered by a 

 common integument, and thus converted into a species of 

 fins. 



I shall conclude with some more general remarks. — In its 

 motion this animal must have resembled the turtle more than 

 any other; and the turtle also, as was before remarked, could 

 we divest it of its shelly case, would present some slight ap- 

 proach in its general proportions to the Plesiosaurus. 



I shall leave to others more conversant than myself with 

 the analogies of comparative anatomy, the infei'ences to which 

 those particulars may lead concerning the habits of this sin- 

 gular animal. 



That it was aquatic is evident from the form of its paddles ; 

 that it was marine is almost equally so, from the remains with 

 which it is universally associated ; that it may have occasion- 

 ally visited the shore, the resemblance of its extremities to 

 those of the turtle may lead us to conjecture ; its motion, how- 

 ever, must have been very awkward on land ; its long neck 

 must have impeded its progress through the water, presenting 

 a striking contrast to the organization which so admirably fits 

 the Ichthyosaurus to cut through the waves. May it not, there- 

 fore, be concluded (since, in addition to these circumstances, 

 its respiration must have required frequent access of air), that 

 it swam upon or near the surface, arching back its long neck 

 like the swan, and occasionally darting it down at the fish 

 which happened to float within its reach ? 



It may, perhaps, have lurked in shoal water along the coast, 

 concealed among the sea-weed, and raising its nostrils to a 

 level with the surface from a considerable depth, may have 

 found a secure retreat from the assaults of dangerous enemies ; 

 while the length and flexibility of its neck may have compen- 

 sated for the want of strength in its jaws and its incapacity for 

 swift motion through the water, by the suddenness and agility 

 of the attack which they enabled it to make on every animal 

 fitted for its prey which came within its extensive sweep. 



The name I have originally given to this animal, Plesiosaurus 

 (approximate to the Saurians), may appear rather vague in this 

 stage of our knowledge, and an ajipellation derived from its 

 peculiar length of neck might be preferred ; but for the pre- 

 sent 



