326 BRITISH FOSSIL REPTILES, 



collected from different localities during the last thirty years, and the collocation of some 

 of these remains so as to prove that the entire carcase of an Iguanodon had been 

 imbedded in the matrix, as in the case of Mr. Bensted's discovery near Maidstone, 

 fossil bony scutes, had they existed in any quantity in the skin of the Iguanodon, might 

 reasonably be expected to have been found associated with the parts of the endo- 

 skeleton. Siich dermal bones have been discovered in connection with other remains 

 of the HylfBOsaurus, and we may, therefore, with more confidence assign its value to the 

 negative evidence in the case of the Iguanodon, and conclude that the surface of its 

 nuge body was defended by thickened epidermis, either coextensive with the chorion, 

 or specially developed and multiplied in the form of scales. 



Size, of the Iguanodon. 



From the comparison, which the few connected portions of the skeleton of the 

 Iguanodon enable us to make, between the bones of the extremities and the vertebral 

 column, it is evident that the hind legs at least, and probably also the fore legs, were 

 longer and stronger in proportion to the trunk than in any existing Saurian. One can 

 scarcely suppress a feeling of surprise that this striking characteristic of the Iguanodon, 

 in common with other Dinosauria, should have been so long overlooked ; since the 

 required evidence, as pointed out in my ' Report on British Fossil Reptiles,'* is only an 

 associated vertebra and long bone of the same individual, or a comparison of the largest 

 detached vertebrae with the longest femora or humeri. This characteristic is, never- 

 theless, one of the most important towards a restoration of the extinct reptile, since an 

 approximation to a true conception of the size of the entire animal could only be made 

 after the general proportions of the body to the extremities had been ascertained. 



It was obvious that the exaggerated resemblances of the Iguanodon to the 

 Iguana misled the Paleontologists who had previously published the results of their 

 calculations of the size of the Iguanodon ;t and, hence, the dimensions of 100 feet in 

 length arrived at by a comparison of the teeth and clavicle of the Iguanodon with the 

 Iguana, of 75 feet from a similar comparison of their femora, and of 80 feet from that 

 of the claw-bone ; which, if founded upon the largest specimen from Horsham, instead 

 of tlie one compared by Dr. Mantell, would yield a result of upwards of 200 feet for 

 the total length of the Iguanodon, since the Horsham phalanx exceeds the size of the 

 largest of the recent Iguana's phalanges by 40 times ! 



But the same reasons which I have assigned for calculating the bulk of the 

 Megalosaurus on the basis of the vertebrae,;}: apply with equal force to the Iguanodon. 



* Reports of the Brit. Association, 1841, p. 142. 



t Mantell, 'Geology of the South-east of England,' p. 314. Biickland 'Bridgewater Treatise,' p. 243. 



J Reports of the Brit. Association, 1841, p. 109. 



