1864, ] DR. J. E. GRAY ON A NEW STAUROTYPUS, 127 
verging towards the centre, where the ridges unite and form a single 
central ridge of granules to the horny tip of the tail. 
This genus has all the characters of the more typical aquatic Ter- 
rapins. The feet are broad, the toes elongated and well webbed; 
and the alveolar edges of the jaws, according to the figure of M. A. 
Duméril (J. c. t. 15), have distinct dentated ridges, like the genera 
Pseudemys and Batagur. M. Duméril’s figure seems to have been 
taken from a badly preserved stuffed specimen. There is a second 
specimen of this very interesting Terrapin now alive in the Zoolo- 
gical Gardens. 
In my description of the genus I have described the axillary and 
inguinal plates as absent. In Mr. Salvin’s specimen they are very 
small, but yet distinctly present, but are more developed on one side 
than on the other, showing that they are variable in this animal. 
9. Description or a New Species or Sraurotyrvs (S. saL- 
_VINIT) FROM GuaTEMALA. By Dr. J. E. Gray, F.R.S., etc. 
Among the interesting series of Tortoises brought by Mr. Salvin 
from Haumanchal, Guatemala, and deposited in the British Museum, 
are two specimens of a Tortoise of the genus Staurotypus, but dif- 
fering from the normal form of that genus in the sternum being 
narrowed and acute in front, like the sternum of Chelydra, which 
genus it resembles in having a crested though short tail. 
I would propose to divide the genus thus :— 
- A. Sternum broad and truncated in front. StTAUROTYPUS. 
1, STAUROTYPUS TRIPORCATUS, Gray, Cat. Shield Rept. B. M. 
47, t. 20 6. 
Hab. Mexico (Wiegmann) ; Vera Cruz (Sallé). 
B. Sternum narrow, tapering, acute in front. STAUREMYS. 
This subgenus has the form of the sternum and the crested tail of 
Chelydra, with the sternal shields of Staurotypus. 
2. Sraurotypus (STAUREMYS) SALVINII. 
Hab, Haumanchal, Guatemala (Salvin). 
Head very large, swollen, crown covered with a thin soft skin; 
face conical, rather produced; nose terminal; mouth inferior; beak 
large, dentated on the edge; chin with two beards; throat warty ; 
skin of body and limbs granular; the fore legs have several slender, 
very broad, arched, band-like shields across the imner side, the 
middle one being the broadest ; toes well developed, strong; upper 
surface covered with a single series of band-like shields, united 
to the claws by a wide, well-developed web; claws 4—5, strong, 
elongate, acute; tail short, conical, angular above, with a central 
