238 



EEPTILIA 



CLASS III 



acetabular portion much extended, and the ischium has an obturator process. 

 Supposed sternal ossifications sometimes occur. 



Camptosaurus, Marsh (Campfonotus, Marsh). Attaining a total length of 

 about 10 m. Cervical ribs short; dorsal vertebrae amphiplatyan ; sacrals 

 not anchylosed. Pubis robust, post-pubis of equal length with the long and 

 slender ischium. Pendent inner fourth trochanter of femur very marked. 

 Proximal tarsals separated. Upper Jura ; Wyoming and Colorado. Kim- 

 meridgian and Wealden ; England. 



Laosaurus, Dri/osaurus, Nanosaurus, Marsh. Upper Jura ; Wyoming and 

 Colorado. 



Hypsilopliodon, Huxley. Premaxillae each with five small deeply-socketed 

 lateral teeth, edentulous and beak-like in front ; nasals elongated. Yertebrae 

 amphiplatyan. Sternum partly ossified. Post-pubis of equal length with the 



I'd - 



Fig. 340. 



laiMnodoii. beriiissartcims, Boul. Wealden; Bernissart, Belgiuut. Skull, i/g. A, Orbit; art, Articular; d, 

 Deutary ; fr, Frontal ; ju, Jugal ; la, Lachrymal ; mx. Maxilla ; N, External nostril ; na. Nasal ; pa, Parietal ; 

 pd, Predentary ; pm.v, Premaxilla ; ptf, Postfrontal ; qu\ Quadrate; quj, Quadrate -jusal ; S, Supratemporal 

 vacuity ; sq, Squamosal ; x, y, Supraorbitals (after DoUo). 



ischium ; proximal tarsals separated ; manus and pes each with four clawed 

 digits. Known by several complete skeletons 1"5 m. long from the Wealden 

 of the Isle of Wight. 



Iguanodon, Mantell (Figs. 340-342). Skull laterally compressed, with 

 large, nearly terminal nostrils, and small antorbital vacuity. Orbits deeper 

 than wide, smaller than the irregularly triangular or elongated lateral temporal 

 vacuity. Supratemporal vacuities of moderate size, separated by the narrow 

 parietals, which meet in a sharp median crest. Two small supraorbital bones 

 above the eye, but no sclerotic ring. Frontals flattened and apparently fused ; 

 nasals elongated. Mandibular suspensorium nearly vertical ; articular portion 

 of the cpiadrate at the base of an unusually deep pedicle. Jugal crescentic, 

 bounding the orbit inferiorly ; quadrato-jugal rather large ; lachrymal small. 

 Premaxillae toothless, but with sharpened margin. Maxillae and dentary 

 with numerous closely-set grinding teeth arranged in a single row ; the teeth 

 when unworn are spatulate, loosely socketed, and with serrated margins ; 

 successional teeth well formed below those of the functional row. Mandibular 



