516 ZOOLOGY. 
Still nearer the birds was the Compsognathus; it was 
only two thirds of a meter (2 feet) long, with a light head, 
toothed jaws, and a very long, slender neck ; the hind limbs 
were very large and disposed as in birds, the femur being 
shorter than the tibia; moreover, the fore legs were very 
small. ‘It is impossible,” says Huxley, ‘to look at the 
conformation of this strange reptile and to doubt that it 
hopped or walked, in an erect or semi-erect position, after 
the manner of a bird, to which its long neck, slight head, 
and small anterior limbs must have given it an extraordi- 
nary resemblance.” The so-called bird tracks of the Triassic 
rocks of the -valley of the Connecticut were all reptilian 
footprints, and without doubt made by Dinosaurs with the 
above-mentioned affinities to the birds. These bird-like, 
colossal lizards appeared in the Jura-Trias Period, and be- 
came extinct in late Cretaceous times. 
Order 11. Pterosauria.—The forms of this order, rep- 
resented by the Pterodactyles, would lead one to infer that the 
group was still more bird-like than the Dinosaurs, and See- 
ley has shown that they have as many and important points 
of similarity to that class as the preceding group. They are 
a sort of reptilian bats, forming links between reptiles and 
flying birds, as the Dinosaurs connect with the ostriches, 
and it is in the hand and foot, which in birds are the most 
characteristically ornithic, that they resemble the ornithic 
type. They also approach birds in their long heads and 
necks, the jaws with or without teeth, the short tail, in the 
skull which is more rounded and bird-like than in other 
reptiles, with large orbits, as also in the form of the brain ; 
while the jaws were probably, in part at least, encased in 
horny beaks. The shoulder girdle was bird-like, and the 
sternum was keeled, but the pelvis and limbs were like 
those of lizards, while the fore-feet were much larger than 
the hinder ones, and the ulnar finger was enormously 
Jong and probably supported a broad membrane, connecting 
the fore and hind limbs, as in bats; moreover, the limb 
bones were hollow, and air-cells were present, so that 
these winged lizards could fly like birds or bats. The jaws 
of the Pterosaurs were completely toothed; those of the 
