44 PROCEEDINGS OP THE GEOLOGICAL SOCIETY. 



Of Neusticosaurus pusillus Prof. H. G. Seeley says, " it is probably 

 the smallest representative of the Plesiosauria yet exhumed ; but it 

 has the greater interest in exhibiting in the hind limbs all the cha- 

 racters of a land animal, while the fore limbs have become paddles, 

 in which a more striking approximation is made to Plesiosaurus than 

 was previously known in any Triassic representative of this order." 

 Connecting links are so important that it is to be hoped that before 

 long the acquisition of less imperfect material than that at Prof. 

 Seeley's command may confirm his views, and afford additional in- 

 formation respecting this highly interesting Sauropterygian. 



Prof. E. Owen's paper " On Generic Characters in the Order Sau- 

 ropterygia " must command the attention and consideration due to 

 the mature opinion of so eminent an anatomist and zoologist, who 

 has made fossil reptiles a special study, and is the founder of the 

 order to which his paper relates. 



The subclass Enaliosauria (Owen), which includes the subjects of 

 both the above papers by Profs. Seeley and Owen, is in several re- 

 spects one of much interest. 



This Society may be said to have a sort of property in it, because 

 it was at one of its meetings, some sixty years ago, that Conybeare 

 and De la Eeche first made known the Plesiosaurus and also added 

 largely to the previously comparatively scanty knowledge of Ichthyo- 

 saurus. Their admirable memoir, printed in vol. v. ser. i. of the 

 Society's Transactions, published in 1821, supplemented by two 

 others which shortly followed it, was so comprehensive that to the 

 illustrious Cuvier it appeared to leave little to be added by subse- 

 quent investigators. Since then, however, large quantities of Enalio- 

 saurian remains have been accumulated (a magnificent series of their 

 skeletons is now displayed in the galleries of the new Museum of 

 Natural History in Cromwell Eoad, and few of the provincial museums 

 of any magnitude are without examples of them) ; and yet many ques- 

 tions concerning these old " Sea-Dragons," as Thomas Hawkins 

 quaintly called them, continue to this day unsettled. 



Thus taxonomists differ much as to the true zoological position of 

 the Enaliosauria. Prof. B. Owen, the founder of this subclass, 

 places it between Labyrinth odonta (Batrachia) and Anomodonta ; 

 whilst Claus, the author of one of the newest works on systematic 

 zoology having a wide reputation, makes Enaliosauria the first order 

 in a subclass Hydrosauria (in which he includes Crocodilia) which 

 he intercalates between Sauria and Chelonia. Claus's order Enalio- 

 sauria comprises three families, Ichthyosauria, Plesiosauria, and 

 Nothosauria. Prof. E. Owen's subclass Enaliosauria contains his 

 two orders Icthyopterygia and Sauropterygia. The former is re- 

 presented in our rocks, as yet, only by the genus Ichthyosaurus ; 

 whilst the latter comprises the four genera Plesiosaurus, Pliosaurus, 

 Nothosaurus, and Placodus (Weusticosaurus would also find its place 

 here). 



As a preliminary to discussing the systematic position of the 

 Enaliosauria, the question whether the alliance of the orders Ichthyo- 

 pterygia and Sauropterygia is a natural one requires examination. 



