1869. ] DR. J. E. GRAY ON THE TORTOISES. 205 
terior end to the back edge of the orbit than from that part to the 
end of the nose; eyes lateral, eyebrows rather convex ; zygomatic 
arch short, narrow, from the middle of the hinder edge of the orbit 
to the upper part of the front margin of the tympanic cavity, which 
is only furnished with a narrow edge. Sheath of the upper jaw with 
straight, closely denticulated edges ; lower jaw strong, very convex, 
and covered with a horny sheath in front. Toes slender, with a few 
hexangular shields above, very broadly webbed; claws small. 
2. PANGSHURA TENTORIUM. 
Skull (as seen through the skin of the preserved specimen) very 
like that of P. teeta, but the crown is rather more produced behind, 
or rather the orbits are more in front of the head; the bony temple 
is broader behind the eyes; and the zygomatic arch is broader, 
being as wide as the upper half of the front edge of the tympanic 
cavity. The horny sheath of the upper jaw is rather sinuous, dis- 
tinctly but closely denticulated. Toes slender, very widely webbed 
to the claws; claws small. 
3. PANGSHURA DURA. 
Skull (as seen through the skin of the stuffed specimen) ovate 
triangular, sides erect ; orbit very large, subsuperior; crown rhombic, 
produced and acute behind, twice as long from the hinder end to 
the back edge of the orbit as the length from that part to the 
end of the nose; zygomatic arch short, convex, the front end form- 
ing part of the crown, and wider than the orbit, and the hinder part 
narrower and only attached to the upper part of the edge of the 
tympanic cavity. Sheath of the upper jaw broad, high, with a 
straight simple edge; lower jaw strong, covered with a convex 
horny sheath in front. Toes slender, broadly webbed to the claws. 
Tribe VI. Ps—EUDEMYDINA. 
19. PSEUDEMYS. 
1. PsEUDEMYS SERRATA. 
A mounted skeleton in the British Museum, from North America. 
Skull solid, crown flat, produced and narrow behind, very broad, 
square, high in front, shelving to the mouth below; the labial edge 
nearly straight, with a notch in front, and minutely denticulated on 
the margin. The zygomatic arch very broad, slightly convex ex- 
ternally ; the mastoid bone produced horizontally, flat above exter- 
nally, and keeled above, with a moderate-sized internal cavity. 
Palate concave behind the internal nostrils. The alveolar surface of 
the upper jaw flat, wide, rather produced behind; inner or palatine 
edge simple, and armed in front with a large tooth on each side of 
the centre, which is produced into a longitudinal sharp-edged irre- 
gular ridge parallel to the outer margin and nearer to it than to the 
inner edge of the alveolar surface. The lower jaw strong, much 
depressed and wide in front, and quite flat on the lower surface ; 
