DINOSAUMA. 293 



in 1832. It consisted of a block of stone measuring 4^ feet 

 by 2 J feet (fig. 99), and included the following parts of the 

 skeleton in almost natural juxtaposition : — io, anterior verte- 

 brae, the first supporting part of the base of the skull ; several 

 ribs, 4, 4 ; some enormous dermal bony spines, 5, 6, 6, which 

 supported a strong defensive crest along the back ; two cora- 

 coids, 7, 7 ; scapulae, 8, 8 ; and some detached vertebrae and 

 fragments of bones. In 1841 the writer shewed that the 

 sacrum was dinosaurian, and included five vertebrae. 



The teeth are relatively small, close-set, thecodont in im- 

 plantation, with a subcylindrical fang and a subcompressed 

 slightly expanded and incurved crown, with the borders of 

 the apical half straight and converging to the blunt apex, 

 but not serrate as in Sceliclosaurus. They indicate rather a 

 mixed or vegetable diet than a carnivorous one. The skin 

 was defended by subcircular bony scales. The length of the 

 Hylaeosaur may have been 25 feet. 



Genus Iguanodon, Mtll. — Eemains of the large herbivor- 

 ous reptiles of this genus have been found in Wealden and 

 neocomian (greensand) strata. Femora, four feet in length, 

 shewing the third inner trochanter, have been discovered. 

 The sacrum included five, and in old animals six, vertebrae ; 

 the claw-bones are broad, flat, and obtuse. There were only 

 three well-developed toes on the hind foot ; and singular large 

 tridactyle impressions in the Wealden at Hastings, have been 

 conjectured to have been made by the Iguanodon. 



With vertebrae, subconvex anteriorly in the neck, but 

 along the rest of the trunk subconcave at both articular 

 extremities ; having, in the dorsal region, lofty and expanded 

 neural arches, and doubly articulated ribs, and characterized 

 in the sacral region by their unusual number and complica- 

 tion of structure ; with a Lacertian pectoral arch, and 

 unusually large bones of the hind limbs, excavated by large 

 medullary cavities, and adapted for terrestrial progression ; — 



