178 DR. J. E. GRAY ON THE TORTOISES. [ Mar. 11, 
zygomatic arch complete, broad in front, narrowed behind and at- 
tached to the upper front part of the tympanic cavity ; mastoid bone 
acute behind, keeled on the outer upper side, hollow; palate flat ; 
internal nostrils anterior, with a short, oblong, slightly sunken con- 
cavity behind, each separated from the other by a blunt ridge; 
alveolar plate very narrow, linear, with a slight ridge on the inner 
margin; upper beak with a smooth edge and an entire, recurved, 
sharp tip. Lower jaw moderately strong, rounded below in front ; 
lower beak with a simple sharp edge, rather produced and acute in 
front, with a slightly concave linear inner margin. 
5. Pyxictemmys, Gray, P. Z. 8. 1863. 
6. Lurremys, Gray, P. Z.8. 1855 & 1863. 
The anatomy of the animal is well described by Bojanus. The 
skull is figured by Cuvier (Oss. Foss. v. t. 11. f. 13-16) and Wagler 
(in N. Syst. Amph. t. 5. f. xv.-xvii.). There is a skeleton in the 
British Museum ; it has a well-developed zygomatic arch. 
7. Norocuetys, Gray, P. Z. 8. 1863. 
** Lobes of the sternum moveable in the young state, often 
becoming anchylosed. 
8. CycLtemys, Gray, P. Z.S. 1855, p. 198, 1863, p. 177. 
The thorax convex or depressed. The sternum flat or slightly 
convex, with the lateral symphyses well marked, truncated before 
and notched behind; the cross suture indistinctly marked and nar- 
row, more or less obliterated in the adult, covered with the produced 
front edge of the ventral shields. The legs covered with large, band- 
like thin plates in front. The toes banded above, the front one 
short, webbed. The hind feet flattened, with the toes broadly 
webbed ; the hinder edge keeled and angularly produced. 
CYCLEMYS ORBICULATA. 
Skeleton in the British Museum, from Java. 
Skull elongate; zygomatic arch rather narrow, distinct. The 
alveolar surface of the upper jaw is narrow, with a well-marked lon- 
gitudinal groove the whole leugth of the outer edge, and with a raised 
internal margin. Edge of the upper jaw rather arched on the side, 
with a small central tooth. The lower jaw with a simple, short 
edge shelving inwards in the centre, and with a rather concave sur- 
face on the inner side, and a sharp, produced central anterior 
process. 
Fam. I]. CueLtyprRapD&. 
Head large, covered with a thin, hard skin, or hard bony plates ; 
temporal muscle large, covered with the skin, and protected on the 
edge by a well-developed band-like zygomatic arch. Eyes lateral or 
