192 DR. J. E. GRAY ON THE TORTOISES. [Mar. 11, 
orbit lateral, superior, on the outer edge of the crown; zygomatic 
arch strong, broad, convex, rather wider than the orbit in front, so 
much so that the circular tympanic cavity behind is rather con- 
tracted in the middle. The palate flat; internal nostrils near the 
centre of the palate, from under a rather convex plate in front, and 
with a central keel in the wide sunken space behind them. The 
alveolar surface of the upper jaw very wide, quite simple, occupying 
all the front of the palate but a central triangular space, without any 
internal ridge. The lower jaw very strong, flattened out in front 
and on the sides of the front, without any gonyx, the upper edge 
simple, with a very broad, shelving, concave inner aveolar surface 
and an acute central point. Toes rather elongate, webbed to the 
claws, with band-like shields above. 
Malaclemmys concentrica, 
Skull in the Museum of the College of Surgeons, no. 1057, with- 
out.horny sheath. The palate flat; the aveclar process very wide, 
smooth, rather convex on the front part of the inner edge. The 
part of the palate behind the internal nostrils broad, slightly sunken, 
