20. TESTUDO. 155 



No enlargocl femoral tubercle ; tiiborcles on 



the front of the tore limb extremely 



large, in three longitudinal series 3(i. tdthii, \). 175. 



A large subconical tubercle on the hind 



side of the thigh 37. ibera, p. 17'5. 



b. Fifth vertebral shield much 

 broader tlian third ; supracau- 

 dal usually divided ; no large 

 femoral tubercle 38. grceca, p. 177. 



2. Hand and foot with four claws. . . . 31). liorsjiddli, p. 178. 



VII. Gular region of plastron much produced ; gular shield single. 



Gular shield truncate 40. anfpdata, p. 178. 



Gular process pointed, hooked upwards. ... -11. i/nijjhunt, p, 170. 



1. Testudo polyphemus. 



Testudo polyphemus, Z>flw<:?. Iie2)t. ii. p. 2o6 (1802); Say, Journ. Ac^ 

 Philad. iv. p. 207 (1824); Harhm, J>-uni. Ac. Fhilad. vi. p. 21 

 (1829) ; lJu7n. &■ Bibr. ii. p. 102 (183oj ; Ilolbr. N. Am. Ilerp. i. 

 p. 25, pi. i. (1842). 



depressa (Cuv.), Gverin, Icon. Ii. A., Hept. pi. i. fig. 1 (1829). 



■ Carolina, Lecotite, Aim. Lye. N. Y. iii. p. 97 (18.'>0). 



aopher, Gray, Cat. Tort. p. 4 (1844), and &Ji. Bcpt. i. p. 5 



(1855). 



Xerobates carolinus, Agassiz, Contr. N. II. TJ. S. i. p. 447 (1857). 

 I'' Testudo australis, Girard, U. S. Riplur. Eupvd., Hop. p. 470 



(1858). 

 Xerobates gopher, Gray, Proc. Zool. Soc. 1873, p. 723. 

 polyphemus. True, Froc. U. S. Kat. Mm. iv. p. 434 (1881). 



8hell considerably depressed, more than twice as long as deep, 

 flattened on the vei-tebral region, neither notched anteriorly nor 

 reverted nor distinctly serrated posteriorly ; nuchal shield present, 

 squarish ; supracaudal undivided ; shields concentrically grooved in 

 the young, often quite smooth in the adult ; vcrtebrals much broader 

 than long and broader than the costals. Plastron large : front lobe 

 bent upwards, extending beyond the carapace, gular region truncate 

 or openly notched ; hind lobe deeply notched ; suture between the 

 gulars as long as or a little shorter than that l)etwcen the humerals : 

 axillarj' and inguinal moderate. Head short and broad, with 

 numerous small and irregular shields, among which a pair of pre- 

 frontals is usually recognizable. Jaws denticulated, upper not 

 hooked, with three larger cusps at the symphysis ; alveolar surface 

 of upper jaw with a strong median ridge, which is nearer the inner 

 than the outer border, and a strong longitudinal median ridge at 

 the symphysis. Fore limb much compressed antero-posteriorly, 

 broadest at the extremity, which is armed with particularly large 

 compressed claws; the distance from the base of the first claw to 

 the base of the fourth in the hind limb equals the distance from the 



