JURASSIC ANIMALS. 



430 



tebral bodies. Eecent discoveries in Kansas show that sclerotic bones 

 were present in this order also.* Sixteen species have been found, in 

 the Jurassic and Cretaceous rocks of Great Britain alone, and one, P. 

 dolichodeirus, was twenty-five to thirty feet long (Fig. 684), with pad- 

 dles six to seven feet long. 



The Pliosaurus (more lizard-like) had the large head and short 

 neck of the Ichthyosaurus (Fig. 688), with the powerful paddles of the 



Fig. 690.— Teleosaurus brevidens: a, skull; 5, side view of snout showing 

 the teeth (after Phillips). 



Fig. 689.— Paddle of a Pliosaurus, x ^. 



Plesiosaurus. A perfect paddle of this animal has been found seven 

 feet long (Fig. 689) ; the animal was probably at least forty feet long. 



Intermedi- 

 ate between this 

 group and the 

 next — inhabit- 

 ers both of 

 land and water 

 — Croccdilians 

 existed in great 

 numbers, and 

 of great size. 



Some, like the Teleosaurus (Fig. 690), were narrow-snouted like the Ga- 

 vials of the Ganges, but had amphiccelous vertebrae like the Enaliosaurs. 

 2. Dinosaurs. — Among these were the largest reptiles — in fact, the 

 largest land-animals — that have ever existed. They were also in many 

 respects the highest of all reptiles, since they possessed many charac- 

 ters which connected them closely with mammals, and especially with 

 birds. 



Connecting: Characters. — The most important of these were: (1.) 

 Large, hollow limb-bones and firm sacrum composed of several consoli- 

 dated vertebrae. These characters show that these animals walked with 

 a free step, the body well borne above the ground, like mammals and 

 birds, and did not crawl in the manner of reptiles. (2.) In many cases 

 the hind-legs were very large and long, and the fore-legs very small in 

 comparison. This, together with the backward elongation of the 

 ischium (Fig. 691 B) — suitable for erecting the body — show that some 



* Williston, Science, vol. 16, p. 262, 1890. 



