SAURIA. 293 



long and thirty-four wide, and sternum twenty-eight inches 

 long. It is frequently seen in mid-ocean floating upon 

 the waves, apparently asleep. 



SPHARGIDID.E, OR SPHARGIS FAMILY. This Family 

 comprises turtles whose general form is something like 

 that of a flattened pyramid, and the body is covered with 

 a thick coriaceous skin, instead of a hard shell. Sphargis 

 is the only genus, and is represented by 5. coriacea, Gray, 

 of the Atlantic and Mediterranean, which is the largest 

 of all turtles, attaining the weight of twelve hundred to 

 two thousand pounds, in some cases. One caught in 

 Chesapeake Bay had a total length of almost eight feet. 



Fossil turtles are found in both continents. 



SUB-SECTION II. 



THE ORDER OF SAURIA, SAURIANS, OR LIZARDS. 



THE Sauria are reptiles which have a long body with- 

 out a shell, a long tail, in most cases four limbs (in some 

 cases only two, in others none), and a large mouth 

 armed with teeth. In general their eyes are furnished 

 with lids, and there is usually an external opening to the 

 ear. Including both fossil and living species the Saurians 

 may be divided into five groups, the Dinosaurs, Croco- 

 dilians (regarded as a distinct order by many naturalists), 

 Lacertians, Enaliosaurs, and Pterosaurs. 



The Dinosaurs include huge fossil saurians, as the 

 Megalosaurus, a carnivorous reptile thirty feet long, and 

 the Iguanodon, an herbivorous reptile which was thirty 

 to forty feet in length or more. 



The Crocodilians comprise the Crocodiles of the Nile, 

 the Gavials of the Ganges, and the Alligators of the 

 warm parts of America. The two first attain the length 

 of thirty feet, and the last fifteen feet or more. The 

 Crocodilians have the body protected by a sort of cuiras? 



