548 ORDER LORICATA 5 GENERAL CHARACTERS. 



large size, and lie over one another like the tiles of a house, so 

 that each is overlapped by the one in front of it, to one-third 

 of its extent. Hence, although this species is not nearly so large 

 as the Green Turtle, the plates are of greater dimensions, as 

 well as of finer quality. Its flesh, however, is neither so palat- 

 able nor so wholesome. One other species may be noticed, the 

 Sphargis, or Leathery Turtle; which differs from all other 

 Turtles, in having the bones covered with a leathery skin, in- 

 stead of with plates. When attacked and wounded, it utters 

 loud piercing cries, which have been heard nearly a mile off. 

 It sometimes attains enormous dimensions; the occurrence of 

 specimens measuring about eight feet in length, and weighing 

 one thousand pounds, being recorded. Its flesh appears to be 

 very unwholesome. 



486. Little is as yet known of the fossil forms of this order ; 

 but, from discoveries made some years since among the Himalaya 

 mountains, it appears that Tortoises must have formerly existed, 

 far surpassing in dimensions the most bulky of the Chelonidae 

 now living. The Colossochelys Atlas, discovered in the Sewalik 

 hills by Falconer and Cautley, measured about eighteen feet in 

 length ; and it seems not improbable that, like the Dinornis, it 

 may have existed down to the human era. 



ORDER II.-LORICATA. 



487. THE animals forming this order, the Crocodiles and 

 Alligators, are placed by some naturalists with the Lizards, with 

 which, in fact, they agree in external form, and, to a considerable 

 extent, also, in general structure. They are, however, in some 

 particulars of their organization, decidedly superior to other 

 Reptiles ; their heart possessing four cavities ( 478), and their 

 lungs being more subdivided than those of Reptiles in general. 

 Unlike the Lizards, the palatine bones form a complete roof to 

 the mouth ; and are destitute of teeth. The jaws are long, and 

 the tympanic bone, to which the lower jaw is articulated, al- 

 though firmly attached to the head, projects backward beyond 



