II. Order CHELONIA. 



Quadrate bone united to the skull, not movable. No teeth; 

 a horny sheath covering the jaws. Body enclosed in a bony 

 shell; dorsal ribs single-headed; no sternum. Anal opening 

 round or longitudinal; copulatory organ present, single. Ovi- 

 parous, the eggs are oblong or round (fig. 102), hard-shelled, 

 in the Cheloniidae soft-shelled. 



The tortoises and turtles of the Indo-Australian region 

 belong to seven families. 



Fig. 102. Eggs of Chelonia. Nat. size. 

 a. of Chelonia mydas (L.), b. of Carettochelys insculpta Ramsay. 



Synopsis of families. 



A. Shell covered with epidermal, horny shields. 



I. Pectoral shields of plastron in contact with the 

 marginals. 



a. Plastral shields 1 1 or 12 Testuditiidae p. 288. 



b. Plastral shields 13 Chelyidae p. 314. 



II. Pectoral shields widely separated from the mar- 

 ginals. 



1 . Tail more than half the length of the shell ; 



plastron small, cruciform Chelydridne p. 287. 



2. Tail not half so long as the shell; limbs 



paddle-shaped, one or two claws Cheloniidae p. 307. 



