IX.—Additional Notices on the Fossil Genera Ichthyosaurus and Plesiosaurus.

Abstract

In 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 Saurian order, it was my object to give a general outline of the facts which my own observation, or that of others, had enabled me, up to that period, to ascertain 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 specimens, 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 supposed 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