C H E L N 1 1. 427 



shown to constitute an Order, when the name of Chelonians ( Chelonia) 

 was applied to them, let these Reptiles be designated under the latter 

 name. 



Furthermore, the order of Chelonians subdivides into two natural 

 sub-orders ; and, since we find, in either of these sub-orders, a family 

 and a generic name, typifying best their respective group,* we deem 

 it rational to call the first Chelonii, and the second Testudinata. 



Cheloniens, BROXGN. in Bull. 8oc. Philom. 1800, 89. Ccv. Regn. Anim. II, 

 1817, 6; 2d ed. II, 1829, 5; &, ed. illustr. Kept. 9. BUM. & BIBB. Erpet. gen. I, 

 1834, 345; &, II, 1835, 1. TEMM. & SCHLEG. in Sieb. Faun. Japon. Erpet. 1838, 1. 

 Chdonia, GRAY, in Ann. nat. Hist. I, 1838, 275; Catal. Tort. Croc. & Amphisb. 

 Brit. Mus. 1844, 3 ; &, Catal. Shield. Kept. Brit. Mas. 1855, 1. HOLBR. N. Amer. 

 Herp. I, 1842, 21. 



The synonyms of Testudinata will be found, further on, under the 

 heading of that sub-order. 



SUB.ORDO I. CHELONII. 



The Marine Tortoises are easily distinguished from the land and 

 fresh-water tribes, and which constitute the sub-order of Testudi- 

 nata. Their body is very much depressed, cordate or subcordate, gene- 

 rally even on the periphery of the carapax ; the plastron, which is 

 always much longer than broad, and immovable, is never completely 

 ossified in the centre, being united to the carapax by a cartilaginous 

 arch. The carapax and plastron, both, are either covered with horny 

 scales or a leathery skin. The ribs remain free at their extremities. 

 They are provided with four limbs, which cannot be withdrawn under 

 the carapax : the anterior pair is much longer than the posterior pair, 

 both of which being constructed to fulfil the act of natation; the digits 

 are very long, individually immovable, firmly united into flippers, 

 pallets, oars, or paddles, very much flattened, rendering their move- 

 ments powerful and fast in water, powerless and slow on land, sandy 

 beaches, and rocks. The hands are about four times longer than the 

 forearms ; and the feet about once again the length of the tibiae or 



* Chelonidae and Chelonia, Tettudinidae and Testudo. 



