XXIV.—On the Fossil Remains of two New Species of Mastodon, and of other vertebrated Animals, found on the left Bank of the Irawadi.

In describing the fossil remains collected by Mr. Crawfurd during his mission to the Burman Empire, and which his liberality has placed in the Museum of the Geological Society, I conceive that I shall best execute the task intrusted to me, by a strict adherence to zoological and anatomical detail; leaving all geological inferences to Dr. Buckland, who has undertaken that department, and who is so well qualified to do ample justice to it. But before I proceed to my descriptions, it is necessary to express my great obligations to Mr. Broderip, the Secretary of this Society, for the very valuable assistance which he has afforded me on several important points connected with the subject. In the arrangement of the materials before me, the system of Cuvier is followed, according to which I have first to treat of the Mastodon. Fossil species of this genus have already been found in America and in Europe, and are so well known at the present day, that it would be superfluous to enumerate the various accounts which have been given of them. But I cannot pass over the “ Ossemens Fossiles ” of M. Cuvier, who has entered so luminously into the history of these extinct animals; more especially as he has, after describing M. giganteum and M. angustidens, given a chapter on certain teeth belonging to the genus Mastodon, which appear to him to indicate the existence of species different from those two which he had already recorded*. The teeth, according to