24 GUIDE TO THE FOSSIL REPTILES, AMPHIBIANS, FISHES. 
Stand O. only three toes, the basal parts of which are arranged exactly 
as in young running birds before the parts consolidate (see 
illustrations of Dinornis on Stand 0). The tail is deep and 
laterally compressed, as if for swimming, and both this and 
the back are strengthened by partially bony tendons lying 
over the vertebral spines. The three-toed footprints of 
Iguanodon are not uncommon in the Wealden rocks, and are 
sometimes found in the Purbeck Beds. Examples are shown 
in Gallery No. 11 (Wall-case 8 and an adjoining stand). 
Fig. 19. —Skull and mandible of Iguanodon bernissartensis, left side-view, 
from tbe Wealden of Bernissart, Belgium ; about one-eighth nat. size. 
The oval nostril is seen in front, the orbit in the face above the hinder- 
most teeth, and the deep and narrow lateral temporal fossa behind. 
The toothless predentary bone is shown at the front end of the man¬ 
dible. (After Dollo.) 
Stand N. Hypsilophodon is a diminutive Iguanodont, of which fine 
Table-ease] portions of skeletons are exhibited in Wealden sandstone from 
the Isle of Wight (Stand N and Table-case 18). It has teeth 
in front of the upper jaw, and its hind feet are four-toed. 
Sub-order 4.—Theropoda. 
Wall-ease The Theropoda (“beast-footed”) are the carnivorous 
Table-ease Dinosaurs, with a lightly-constructed skeleton and sabre-like 
’19. teeth in sockets. Most of them seem to have been shaped 
like Iguanodon and walked on their hind legs ; but their hip¬ 
bones are different, and more nearly resemble those of the 
Sauropoda and the crocodiles. They are found in all 
Mesozoic rocks both in Europe and in North America (Fig. 
