XXX.--Notice of the discovery of a new Fossil Animal, forming a link between the Ichthyosaurus and Crocodile, together with general remarks on the Osteology of the Ichthyosaurus

In the course of a series of observations on the organic remains contained in the lias in the vicinity of Bristol, my attention was particularly attracted by the numerous vertebræ of oviparous quadrupeds occuring in that formation. Of these a considerable portion obviously belonged to the Ichthyosaurus; the remaining, and larger division, presented vertebræ of forms considerably differing from each other, but which, from some general analogies, I was persuaded had all belonged to different places in the vertebral column of a single species; and I ventured even to point out those places, from a comparison with those of the crocodile to which they bore a strong general resemblance, yet at the same time combined with so many material points of difference, as to prove that the animal from which they were derived must have constituted a separate genus. At this period, I was fortunate enough to associate in my researches a colleague equally able and zealous, whose name stands at the head of this paper. The numerous important and illustrative specimens which he placed at my disposal, proved of material aid, and still more so his general acquaintance with the subject, of which I subsequently enjoyed the fullest advantage; so that the facts now submitted to the Society must be considered as the fruit of inquiries prosecuted by us in common. A skeleton of the animal in question, deficient only in the bones of the head, preserved in the well known collection of Col. Birch, (who most liberally allowed