194 SUPPLEMENTAUY NOTES. 



The occurrence of fossils of this nature in the strata forming the districts denominated ihe 

 Wealds of Sussex and Kent, was first brought under the notice of geologists in 1822, in ray- 

 work on the " Fossils of the South Downs," in which the remains of several unknown reptiles 

 were described ; and among them the teeth and bones of that extraordinary herbivorous lizard, 

 the Iguanodon, on which I am induced to offer a few observations in this place ; the recent dis- 

 covery of some previously undetermined parts of the skeleton, having materially elucidated the 

 structure and economy of the original.' 



Since the first announcement of the discovery of the remains of the Iguanodon, vast quantities 

 of bones belonging to a great number of individuals of all ages have been collected ; but until a 

 few years since, not a vestige of the jaws had been observed, notwithstanding the most diligent 

 research. In the early part of the year 1848, I was surprised and highly gratified by receiving 

 from Capt. Lambart Brickenden (at that time a personal stranger to me), who then resided at 

 Warminglid, near Cuckfield, in Sussex, the greater part of the right side (or ramus) of the lower 

 jaw, with several successional teeth in their natural position, of an adult Iguanodon.^ See p. 202. 



In the course of last summer I obtained a very instructive fragment of the middle part of the 

 right ramus of the lower jaw of a much larger Iguanodon, found by Mr. Fowlestone, with some 

 enormous bones of the extremities, in the Wealden strata of the Isle of Wight. A portion of 

 the upper jaw (without teeth) was discovered some years since in Tilgate Forest, and is deposited, 

 with the whole of the collection I formed at Brighton, in the gallery of organic remains of the 

 British Museum. These three specimens are the only parts of the jaws of the Iguanodon, with 

 the exception of a fragment of the angular bone, that I have had the opportunity of examining. 

 The other portions of the skeleton hitherto discovered are the following : the tympanic bone ; ' 

 cervical, dorsal, lumbar, and caudal vertebrEe, and chevron bones ; ribs ; the iliac bones, and 

 sacrum composed of six anchylosed vertebrae ; * the coracoid, scapula and clavicles ; humerus, 

 radius ? metacarpals ; femur, tibia and fibula, metatarsals and ungueals. The cranium, carpals, 

 and tarsals, have not been discovered. 



With the exception of the assemblage of bones promiscuously grouped together in a block of 

 Kentish rag (of the greensand formation), found in a quarry near Maidstone, by Mr. Bensted/ 



' The following is the description of the specimens first discovered, given in the " Fossils of the South Downs ; or, Illus- 

 trations of the Geology of Susses," 1 vol. 4to. 1822 : " Incisors and molar teeth evidently belonging to the same species of 

 animal: they differ from any previously known; the masticating surface is perfectly smooth and rather depressed in the 

 centre; these teeth consist of the crown only, and are quite solid. An incisor tooth 1.3 inch long Is slightly bowed and 

 smooth on its inner surface ; but it has externally a ridge which extends longitudinally down the front. Its sides are angular 

 and the edges finely crenated." From the resemblance of these teeth in their general form to those of the Iguana, a common 

 land lizard in the West Indies, I subsequently proposed the name of I()\ianodon (implying an animal having teeth like the 

 Iguana) for the fossil reptile. The teeth of an Iguana four or five feet long are not larger than those of a mouse; the 

 Iguanodon's teeth are as large as the incisors of the rhinoceros. The Iguana's teeth, when used, are chipped off at the points, 

 no existing reptile being capable of performing mastication; the teeth of the Iguanodon, on the contrary, are ground down 

 like the worn molars of herbivorous mammalia, as I pointed out in my first memoir in the Philos. Trans. 1825. 



- This beautiful and most instructive specimen is now in my possession ; it is figured of the natural size in Philos. Trans. 

 Part ii. for 1848, Plate XVI., as well as the portion of upper jaw in the British Museum, Plate XIX. The character of the 

 upper and lower teeth of the Iguanodon are well represented in Plate XVIII. of the same memoir. 



A specimen very similar to that discovered by Capt. Brickenden, but of a young individual, was found soon afterwards 

 in a quarry near Horsham ; but I was not allowed the privilege of figuring or describing it ! 



" This may or may not belong to the Iguanodon : no tympanic bone has been found in such connexion with other parts 

 of the skeleton as to afford certain proof that this maxillary element is referable to the Iguanodon. 



* In the Megalosaurus, the sacrum consists of five anchylosed vertebrje. 



= This most instructive specimen is in a glass-case on the floor near the window, in the middle room of the Gallery of 



