Since the description of the fossils on which the genus and species ( Megalosaurus Bucklandi ) was founded, the additional specimens have been, mainly, parts of the trunk and limbs. To the mandibular and dental fossils have been added two portions of the upper jaw, now in the Oxford Museum, on which Professor Phillips has founded the restoration of the skull given in Diagram lvii. of his ‘Geology of Oxford’. Acceptable, therefore, were the additional cranial and dental evidences obtained by Edward Cleminshaw, Esq., M.A., F.G.S., of Greenhill, Sherborne, Dorset, from the freestone of the ‘Inferior Oolite,’ near Sherborne J. Blocks of this stone were in course of preparation for a building, when, indications of imbedded fossils being detected by Mr. Cleminshaw on fractured surfaces of the quarry-stones, he withdrew all such from the building-yard and transmitted them to the British Museum for identification. Further requisite development of these remains having been there carried out, the following descriptions and drawings are now submitted to the Geological Society. In the section devoted to the genus Megalosaurus in vol. i. pp. 329-354 of the undercited work w the materials for a reconstruction of the skull were limited to portions of the mandible and divers teeth therein implantcd or detached. The most instructive of these was a portion of the lower jaw, in the collection of His Grace the Duke of Marlborough, from the same formation (Oolitic Slate, Oxford) as that which had afforded Buckland the materials for the species which