316 CLASS XV. 



last-named species the article Crocodile by BoRY ST VINCENT, Diet, class. 

 d'Hist. natur. v. p. in, and the fig. PL 119, Liv. 14, No. 8.) 



Gavialis OPP., Rhamphostoma WAGL. Teeth equal; upper jaw 

 with margin straight. Head narrowed abruptly with a very long 

 cylindrical snout. 



Sp. Crocodilus gangeticus, Lacerta gangetica GMEL., LAC. Quadr. ovip. I. 

 PI. 15 ; the cranium figured Ann. du Mus. X. PL i, figs. 2, 10, xii. PI. i, 

 figs. 6, 7, the nuchal shields x. PL 2, fig. 1 1 ; the only species of this sub- 

 genus hitherto known. Jt lives in the Ganges, attains a remarkable size, 

 and feeds principally on fish. The adult male has a large tubercle at the 

 extremity of the upper jaw; compare hereon GEOFFE. SAINT-HILAIBE 

 Mem. du Mus. 1825, pp. 100 115, PI. 5. 



OEDER VI. Chelonii. 



Cavity of tympanum distinct; membrane of tympanum in most 

 naked, in some covered. Eyes with three eyelids. Teeth none. 

 Feet four. Body covered with a double shield, the upper com- 

 posed of confluent ribs, the lower of the sternum. 



Family XXIII. Chelonii. (Characters of the order those 

 also of the single family.) 



Tortoises. They form with LINNAEUS only a single genus Testudo, 

 with 15 species; at present more than 130 are known. On the 

 composition of the shields we have already spoken shortly, (p. 207). 

 The scapula and the bones of the pelvis are situated under the ribs 

 and the spinal column; the muscles which move the limbs are 

 covered by the shields. In the vertebral column the seven cervical 

 vertebrae with the first dorsal vertebra, two or three sacral and the 

 caudal vertebrae, are alone capable of free motion. Ten dorsal ver- 

 tebrae, on the contrary, are immoveably connected with the angular, 

 flat, bony pieces, which form the middle row of the dorsal shield. 

 With these bony pieces the flattened expansions of the ribs are 

 connected on each side by suture; finally, the dorsal shield is 

 bordered by eleven bony pieces on each side. The dorsal shield, 

 consisting of these pieces, is in some tortoises flatter, in others more 

 round, and especially in the land -tortoises is much arched. As to 

 the sternal shield, we have already stated above (p. 207) that 

 it consists of nine pieces ; these leave between them open spaces 

 in the sea-tortoises (turtles), and in the three-nailed freshwater 



