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 A HISTORY OF SUSSEX sagittirostris, which certainly does not belong to the genus whose name it bears, is typified by a specimen from the Hastings Sands of St, Leonards, now preserved in the British Museum among the Beckles collection. From an historical point of view the most interesting of the extinct reptiles from the Wealden of Sussex is however the huge dinosaur to which Mantell gave the name of Iguanodon, on account of a supposed resemblance between its teeth and those of the tropical American lizards known as iguanas. The history of the discovery, as told by Mantell,' is as follows : ' Soon after my first discovery of remains of large verte- brated animals in the strata of Tilgate Forest some teeth of a very remarkable character in a block of stone on the roadside particularly engaged my attention from their dissimilarity to any that had previously come under my notice. Additional examples were soon discovered, and at length I obtained a series of teeth in various conditions, from the pointed incised tooth of the young reptile to the obtuse, worn, flat crown of the adult.' To the reptile indicated by these teeth the name Iguamdon was applied by Mantell in 1825, but it was not till 1832 that H. von Meyer described the species as /. mantelli. Remains of this reptile were subsequently obtained from Battle, Cuckfield, Hawkbourne, Hastings, Horsham and Knellstone ; but it was not till comparatively recently, when entire skeletons were discovered in Belgium, that the true structure of the skeleton of the iguanodon was realized. These Belgian specimens showed individuals of two sizes, the smaller being identified with /. viantelli, and the larger described as a second species with the name of /. bernissartensis. Both types occur in the Sussex Wealden. Iguanodon was an herbivorous reptile, walking on its three- toed hind limbs, with the aid of some support from its long and powerful tail. The largest individuals stood but little short of 20 feet in height. Their three-toed footprints have been preserved in the Wealden sand- stones of Hastings and Bexhill. Two other species of iguanodon, /. dawsoni and I.Jittoni, have been described from the Wadhurst Clay of Hastings, and a third (/. holling- toniensis) from the same stratum at Hollington. The much smaller but alUed dinosaur known as Hypsilopbodon foxi, typically from the Wealden of the Isle of Wight, is also recorded from Cuckfield. A totally different type of dinosaur is indicated by a huge bone of the fore-limb (humerus) from Tilgate Forest, described by Mantell under the name of Pelorosaiirus conybeari, and now in the British Museum. American specimens show that the huge reptiles of this type were herbivorous and quadrupedal, with a length of 60 feet or more. The bodies of their vertebrae were excavated into large chambers. Such a vertebra has been obtained from the Wealden of Hastings, and may belong either to Pelorosaurus or to an allied form (typified by a tooth from the Isle of Wight) known as Hoplosaunts armatus. Smaller vertebra of a similar type from Cuckfield and Hastings belong to a 1 Wonden of Geology, i. 436. 36