10. 
ee 
12. 
DR. J. E. GRAY ON THE TORTOISES, [ Mar. 11, 
obliquely longitudinal, with a short concavity behind each. 
Sternal callosities two, lateral, narrow. D. subplana. 
PLatype.tis. Head oblong, rather depressed ; face moderate, 
rounded in front. Front of the palate with a very wide, shal- 
low concavity, which is rather narrowed and rounded in front, 
and gradually dilated behind. Alveolar surface of the jaws 
flat, rather wider behind, of the upper jaw flat in front, rather 
wider on the hinder part of the sides, with a raised longi- 
tudinal subeentral ridge; of the lower jaw oroad, flat in 
front, with a sharp front edge, narrow in the front part and 
rather dilated on the hinder part of the sides, with a deep 
central longitudinal groove. Sternal callosities four; the late- 
ral ones twice as wide on the inner as on the outer side; the 
hinder triangular, front edge sinuous and wider than the length 
of the straight inner sides. P. ferox. (From Pennant’s spe- 
cimen. ) 
Tyrsr. Head elongate, face elongate, conical, narrow in front ; 
forehead shelving. Skull, underside scarcely bent down in 
front. Palate nearly flat ; central longitudinal concavity in front 
of the internal nostrils wide, much wider behind ; internal nos- 
trils small, rounded, with a short concavity behind each. The 
alveolar process of the upper jaw linear, ‘elongate, scarcely wider 
behind. Lower jaw rather broad, with a shelving concavity on 
the upper surface in front, with a sharp alveolar edge which is 
rather wider and has a linear elongate concavity on the upper 
surface of the hinder half of the sides. Sternal callosities four, 
lateral and anal; anal triangular, rather broader than long. 
The hinder costal bones short, forming together a semicircle 
which is about two-fifths of the width of the costal pieces before 
them. Z. nilatica. 
CauuintA. Head small, face short, tapermg in front. Ante- 
rior palatine groove (in head with beak) narrow, linear, deep. 
Alveolar edge of the beak and upper jaw narrow, linear, taper- 
ing behind; of the lower jaw rather wide, shelving inwards, 
with a sharp edge in front, and narrow, short, and tapering to 
a point behind. Sternal callosities four, lateral and anal. C. 
microcephala and C. spicifera. 
g. Sternum dilated behind, with a flap on each side covering the 
hind legs. 
* Margin of dorsal disk cartilaginous, without marginal bones. 
13. 
Anterior central palatine groove short, triangular, broader be- 
hind. African. 
CYcLANostEus. Sternal callosities 15. Alvcolar surface thin 
in front, broad on the sides. C. senegalensis. 
