DINOSAURIAN REPTILES. 515. 
Fig. 451) in which the jaws are much narrower, is over four 
and a half metres (14 feet) long. It inhabits the rivers of 
Florida where it is very rare, and also the West Indies and 
South America... The cayman of Guiana belongs to a dis- 
tinct genus, Caiman, and is characteristic of the rivers of 
tropical South America. 
Order 10. Dinosauria.—We now come to reptiles which 
have more decided affinities as regards their skeleton (the 
only parts preserved to us) to the:birds, especially the os- 
triches, than any reptiles yet mentioned ; while the Dino- 
saurs were genuine reptiles, in the pelvis and hind limbs, 
including the feet, they approached the birds. This is seen 
especially in the ischium, which is long, slender, and inclined 
backwards as in birds. In the hind limbs the resemblance 
to birds is seen ; among other points, in the ascending pro- 
cess of the astragalus, in the position of the farther (distal) 
end of the fibula, and in their having only three functional 
toes. The fore limbs were shorter and smaller than the 
hind extremities, sometimes remarkably so. Moreover, the- 
limb-bones, vertebre, and their processes were sometimes. 
hollow; the sacrum consisted of four. or five consolidated. 
vertebree, in this respect anticipating the birds and-mam- 
mals. They walked with a free step, like quadrupeds, 
instead of crawling like reptiles; some walked on the hind. 
legs alone, making a three-toed footprint, occasionally 
putting down the forefoot, like the kangaroo. The lar- 
gest Dinosaurs were the Jgwanodon, which was from ten. 
to sixteen metres (30-50 feet) in length, and the Cama- 
rasaurus (Atlantosaurus) which was about twenty-seven 
metres (80 feet) in length. The Cetiosawrus had a length of 
from twenty to twenty-three metres (60-70 feet). The Ha- 
drosaurus stood on its ponderous hind legs, with a stature of 
over eight metres (25 feet). These were bulky, inoffensive, 
herbivorous monsters, able to rise up on their hind feet and: 
browse on the tops of trees; their undue increase was: 
prevented by carnivorous forms like Lelaps, which was am 
active, possibly warm-blooded Dinosaur, with light, hollow 
bones, large claws, and serrate, conical teeth. It stood six 
metres (18 feet) high, and could leap a distance of ten 
metres through the air. (Cope.) 
