IX. — Additional Notices on the Fossil Genera Ichthyosaurus 



and Plesiosaurus, 



By THE Rev WILLIAM D. CONYBEARE, m.g.s. &c. 



[Read May 3, 1822.] 



xN the former communication which I had the honour of submitting to the 

 Society, on the subject of the fossil remains of animals belonging to the Sau- 

 rian order, it was my object to give a general outhne of the facts which my 

 own observation, or that of others, had enabled me, up to that period, to ascer- 

 tain concerning the genus Ichthyosaurus ; and to introduce to the knowledge 

 of the public a new genus, which my own inquiries, assisted by those of Mr. 

 De la Beche, had enabled me to constitute, and to which I appropriated the 

 name of Plesiosaurus. 



It is my present intention to redeem the pledge I gave of endeavouring to fill 

 up the outlines which I then offered, so far as the additional facts gathered in the 

 researches of another year, the examination of many new and illustrative spe- 

 cimens, and my correspondence with scientific friends, have enabled me to do 

 so. Were I at liberty to acknowledge all my obligations to those friends, I 

 should at once disclaim for myself a large share of any merit that may be sup- 

 posed to be attached to the prosecution of these inquiries, and at the same 

 time confirm the results I have to state by authority far superior to my own. 

 And I wish it to be understood, that I have again received, throughout, the 

 assistance of Mr. De la Beche, and continued to derive material information 

 from the fresh specimens which have found their way into the collection of 

 Colonel Birch. 



ICHTHYOSAURUS. 



The new materials which have been collected respecting this genus will 

 enable me to lay before the Society an examination of many points concerning 

 its structure, which before could be only generally stated; a description of some 

 parts of the skeleton previously unascertained, particularly those connected with 



