1158 



CLASS REPTILIA. 



forms with the undermentioned genus Camptosaurus. I. Daivsoni is 

 a form intermediate in size between I. Mantelli and I. bernissartensis, 

 characterised by the less compressed centra and lower arches of the 

 dorsal vertebra; and also by the form of the ilium (fig. 1060, //), 

 which is of great depth, and has a deep and rounded postacetabular 

 process, while the preacetabular process has a horizontal inferior 

 plate. In the smaller I. Fittoni the ilium is equally deep, but has 

 the postacetabular portion narrowed to a point laterally, with a dis- 

 tinct inferior horizontal plate ; while the sacrum has laterally com- 



Fig. 1060. — Left pelvic bones of Lower Wealden Iguanodons. One-sixteenth natural size. //, 

 Ilium of Iguanodon Daivsoni; P, Imperfect pubis of do. ; Is, Ischium of /. hollingtoniensis ; 

 a, Obturator process of ischium. 



pressed vertebrae like those of I. Mantelli. The posterior portion 

 of the ilium of this species is indeed almost indistinguishable from 

 that of Camptosaurus (fig. 1052). Finally, in I. hollingtoniensis ; 

 which agrees approximately in the proportions of the limbs with 

 I. Mantelli, the femur had a curved shaft and pendant trochanter 

 as in Camptosaurus (fig. 1057, b) ; while the sacrum had the ver- 

 tebras remaining separate from one another, with their inferior 

 surfaces flattened, as in that genus, with which this species also 

 agreed in the contour of the ischium (fig. 1060, Is), which has a 

 stout shaft not twisted upon itself. This species agreed, however, 



