514 



zooLoa r. 



vertebr.-B of E. ■platyurus Coi^e, of the New Jersey marl- 

 beds, had vertebrae nearly as large as those of an elephant, 

 while the creature was whale-like in bulk, the neck long and 

 fiexiljle, the paddles short. The skull was light, with a 

 long, narrow, very flat muzzle It must have been the ter- 

 ror of those times ; it was about tifteen metres (45 feet) 

 in length. (Cope.) 



Ordvr '■). Crocodilia. — The crocodile, caiman, gavial, and 

 aUigator are the types of this well-known group. They pre- 

 sent a decided step in advance of other reptiles, tlie heart 

 approaching that of birds, in having the ventricle comjoletely 

 divided by a septum into two chambers ; the venous and arte- 

 ]'ial blood mingle outside of the heart, not in it, as in the 

 foregoing living orders. The brain is also more like that of 

 birds, the cerebellum being broader than in the other rep- 

 tiles. The nostrils are 

 capable of closing, so 

 that crocodiles and 

 alhgators draw their 

 prey under the water 

 and hold them there 

 until they are drown- 

 ed ; but they are 



Fig. 451. -Head of the Florida Ciocodile.-After obliged to drag them 



^^°™'"^''y- asliore in order to eat 



them. The skin is covered with bony, epidermal scales. The 

 conical teeth are lodged in sockets in the jaws. The vertebrae 

 are concave in front and convex behind, or the reverse ; the 

 quadrate bone is immovable. The feet are partly webbed. 

 The crocodiles and gavials appeared during the Jurassic pe- 

 riod, but the early forms were marine and like gavials, the 

 head being long and narrow in front, with biconcave verte- 

 brfe. They lay from twenty to thirty cylindrical eggs in the 

 sand on river banks. The crocodiles are distributed through- 

 out the tropics, even Australia ; the gavials are mostly con- 

 fined to India and Malaysia, and also Australia. The group 

 is rej^resentcd in the Soutlierii States by the alligator {A. 

 Missisfiijjpiensis Daudin). It is nearly two metres (10-12 

 feet) long; while the Florida crocodile (C. actitus Cuvier, 



