February 25, 1841.
Sir JOHN WILLIAM LUBBOCK, Bart., V.P., and Treasurer,
in the Chair.
The Right Honourable Lord Viscount Melbourne, and the Rev. Mark Aloysius Tierney, were balloted for, and duly elected into the Society.
The reading of a paper, entitled, " Memoir on a portion of the Lower Jaw of an Iguanodon, and other Saurian Remains discovered in the strata of Tilgate Forest, in Sussex." By Gideon Algernon Mantell, Esq., LL.D., F^R.S., was resumed and concluded.
When the author communicated to the Royal Society, in the year 1825, a notice on the teeth of an unknown herbivorous reptile, found in the limestone of Tilgate Forest, in Sussex, he was in hopes of discovering the jaws, with the teeth attached to it, of the same fossil animal, which might either confirm or modify the inferences he had been led to deduce from an examination of the detached teeth. He was, however, disappointed in the object of his search until lately, when he has been fortunate enough to discover a por- tion of the lower jaw of a young individual, in which the fangs of many teeth, and the germs of several of the supplementary teeth, are preserved. The present paper is occupied with a minute and circumstantial description of these specimens, and an elaborate in- quiry into the osteological characters and relations presented by the extinct animals to which they belonged, as compared with existing species of Saurian reptiles ; the whole being illustrated by numerous drawings. The comparison here instituted furnishes apparently con- clusive proof that the fossil thus discovered is a portion of the lower jaw of a reptile of the Lacertine family, belonging to a genus nearly allied to the Iguana. From the peculiar structure and condition of the teeth it appears evident that the Iguanodon was herbivorous ; and from the form of the bones of the extremities it may be inferred that it was enabled, by its long, slender, prehensile fore-feet, armed with hooked claM^s, and supported by its enormous hinder limbs, to pull down and feed on the foliage and trunks of the arborescent ferns, constituting the flora of that country, of which this colossal reptile appears to have been the principal inhabitant.
Some particulars are added respecting various other fossil bones found in Tilgate Forest, and in particular those of the HylcBosaurus, or Wealden Lizard (of which genus the author discovered the re- mains of three individuals), and of several other reptiles, as the Megalosauriis, Plesiosaurus, and several species of Steneosaurus^ Pterodactylus, and other Chelonia, as also one or more species of a bird allied to the Heron. All these specimens are now deposited in the British Museum.
A paper was also read, entitled, "On a Theorem of Fermat." By Sir John William Lubbock, Bart., V.P., and Treas. R.S.
