ANNIVERSARY ADDRESS OF THE PRESIDENT. XXIX 



more specialized and studied in minuter detail, this work ■will always 

 be regarded as a striking proof of the ability and knowledge of the 

 authors. 



It was, however, in 1821 (April 6) that Mr. Conybeare commu- 

 nicated to the Society that remarkable Palseontological paper which 

 excited so much interest at the time, and established in the most 

 satisfactory manner the propriety of estabhshing a new genus of Bep- 

 tilia, forming an intermediate link between the IchtJiyosaurus and 

 Crocodile, to which Mr. Conybeare gave the name of Plesiosaurus. 



The discovery of immense vertebrae of oviparous quadrupeds in the 

 Lias near Bristol had attracted the attention of Mr. Conybeare, who 

 quickly recognized the difference between those belonging to the 

 Ichthyosaurus and others, which evidently, in his opinion, were por- 

 tions of a different animal. With a singular acumen and rare sa- 

 gacity, he placed the detached vertebrae in their proper position, and 

 finally established his new genus, for which he adopted the name 

 Plesiosaurus, as expressing its near approach to the order Lacerta. 



For the whole group of animals which approximate, on the one 

 hand, to the Crocodiles in general organization, and yet have been 

 provided with such specific organs as were necessary to enable them 

 to live, at least principally, in the sea, Mr. Conybeare proposed the 

 name Enalio-sauri, as a classic appellation for the whole order ; and 

 he observes of the genera composing it, that even the Ichthyosaurus, 

 which recedes most widely from the forms of the Lizard family, and 

 approaches nearest to those of fishes, exhibits in its osteology a beau- 

 tiful series of analogies with that of the Crocodile, and which widely 

 remove it from fishes. 



In this paper he then described in the minutest detail the osteology 

 of the Ichthyosaurus, and exhibited a knowledge of anatomy which 

 excited the admiration of every one. He then examined with equal 

 care the relics of the new genus, which, although at that time not 

 complete, were sufficient to enable Mr. Conybeare to conclude that 

 the vertebral column recedes from that of the Ichthyosaurus in all 

 the points in which the latter approaches to the fishy structure, and 

 that the invertebral substance must have been disposed much as in 

 Cetacea ; and that, from the locking together of the articulating pro- 

 cesses, it must have had much less flexibility than in the Ichthyo- 

 saurus or in fishes. In examining also such portions of the paddles 

 as could be arranged in order, he comes to a similar conclusion in 

 another direction, namely, that the paddles of the Plesiosaurus are 

 intermediate in character between those of the IchtJiyosaurus and the 

 Sea-turtles ; and thus in every respect he laid a sound foundation for 

 his new genus. 



It is to be remarked that this paper was given as the joint pro- 

 duction of Mr. Conybeare and Sir Henry Delabeche, to whom Mr. 

 Conybeare most liberally ascribed a full share of the merit of the 

 discovery ; but, allowing Sir Henry every praise for his assistance 

 in that discovery and in all the geological details, I believe the sa- 

 gacity and skill exhibited in the osteological details and reasonings 

 have always been ascribed to Mr. Conybeare. 



