196 DINOSAUEIA. 



shaped in section than in the Euiguanodont group ; sacrals with 

 flattened haemal surfaces. 



In the one species in which the pelvis (fig. 39) is known, the 

 ilium has its postacetabular portion long, deep, and rounded 

 terminally, without inflexion of the superior border; the ischium 

 has a hammer-shaped head, of which the pubic process is separated 

 by a long notch from the obturator process ; the shaft is without 

 twist, stout, and moderate in length. 



This group connects Hypsilophodon and Camjptosaurus with the 

 Euiguanodont group. 



Iguanodon prestwichi, Hulke 1 . 

 Syn. Cumnoria prestwichi, Seeley 2 . 



Typically of very small size. The arches of the anterior dorsal 

 vertebrae tall, with the rib-facet not extending to the summit of the 

 platform ; four sacral vertebrae. Teeth simpler than in the Euigua- 

 nodont group. Pelvis and limbs imperfectly known. 



Hah. Europe (England). 



R. 716-8. Casts of the calcaneum and astragalus. The originals, 

 which belong to the type skeleton, were obtained from the 

 Kimeridge Clay of Cumnor-Hurst, Oxfordshire, and are 

 preserved in the Museum at Oxford ; they are figured by 

 Hulke in the ' Quart. Journ. Geol. Soc' vol. xxxvi. pi. xx. 

 figs. 3-5. Made in the Museum, 1880. 



\ Iguanodon dawsoni, Lydekker 3 . 



Typically intermediate in size between /. mantelli and I. bernis- 

 sartensis. Arches of anterior and middle dorsal vertebrae lower than 

 in /. prestiuichi, and the rib-facet rising to summit of platform; 

 probably five vertebrae in sacrum; spines of caudals very long. 

 Preacetabular process of pubis narrow. The scapula provisionally 

 referred is relatively wide. 



Hah. Europe (England). 



All the following specimens are from the Wadhurst Clay, or Lower 

 Wealden, and belong to the Daivson Collection. Purchased, 



1884-87. 



R. 798. A (probably) middle dorsal vertebra ; from near Hastings, 

 {Fig.) Sussex. One of the types ; described and figured by the 



1 Quart. Journ. Geol. Soc. vol. xxxvi. p. 433 (1880). 



2 Rep. Brit. Assoc, for 1887, p. 698 (1888). 



3 Quart. Journ. Geol. Soc. vol. xliv. p. 51 (1888). 



