THE REIGN OF REPTILES. 191 



had a head twelve inches in length, indicating a "snapping 

 turtle" of the formidable length of six feet. The power of 

 such an animal may be estimated by comparison with the 

 familiar " snapper" of modern times. 



But the most abundant of all the Cretaceous reptiles of 

 the Atlantic coast were Crocodilians. At the time of which 

 Ave speak they must have literally swarmed along what is 

 now the river-front of Philadelphia. They peopled every 

 pool and lagoon along the cretaceous shore of Pennsylva- 

 nia. The Deinosaurs, however, were the great feature of 

 the bayou and the estuary. Like their kindred of the Old 

 World, they rivaled in bulk the yet future mammoth and 

 mastodon. "They exceeded these," says Professor Cope, 

 "in their bizarre and portentous aspects; for some have 

 chiefly squatted, some leaped on the hind limbs like the 

 kangaroo, and some stalked on erect legs like the great 

 birds, with small arms hanging uselessly by their sides, 

 and with bony visage surveying land and water from 

 their great elevation." 



One of the most remarkable of these reptiles was the 

 Lselaps (X. aquilunguis, Cope), a carnivorous kangaroo-like 

 quadruped twenty-three feet in length. It seemed a rude 

 attempt of Nature to realize the notion of a bird in the 

 framework of an alligator. It walked entirely on its hind 

 limbs, or leaped like the kangaroo. " Its toes were long 

 and slender, and probably similar in number and form to 

 those of a bird of prey. They were armed with flattened 

 hooked claws, which measured from ten inches to a foot in 

 length, and, like those of the eagle, were adapted for grab- 

 bing and tearing prey. The teeth were adjuncts in this 

 appropriation of animal life; they were curved, knife- 

 shaped, and crimped or serrate on the margin, and adapt- 

 ed like scissors for cutting" (Fig. 15). This was the most 

 formidable land carnivore of the continent, and second to 



