108 
ZOOLOGICAL LITERATURE. 
* Palate concave^ with a narrow deep groove of equal width in front 
> of the large internal nostrils, which have two very large grooves 
behind them, and which are (Contracted, and overlapped on the sides 
by the alveolar plates. 
PotamoeJielys, Gray, p, 85; type Trioriyx javanicus (Geofii’.); 
skull, figs. 7 & 8. T. 'perocellatm (Gray), T. frenatus (Gray), 
T. tuhercidatus (Cant.), and Potamochelys (?) microcephahis appear 
to belong to this genus. 
** Palate fiat, with a broad shallow groove of equal width in front of 
the large posterior internal nostrils, which have two short deep 
grooves behind them. 
Tyrsej Gray, p. 87 ; type Trionyx cegyptiaGus (Schweigg.). 
B. The typical forms with the head elongate^ face very short, 
eyes anterior are subdivided thus : — 
a. Skull short and broad, much depressed ; alveolar edge of both jaws 
flat, simple : Pelochelys, Gray, p. 89 ; type P. cantorii (Gray) ; skull, 
figs. 9 & 10. To this genus also belong Pelochelys cumingii (Gray) and 
Trionyx hihronii (Owen). 
h. Skull elongate ; forehead shelving, much produced behind ; nose very 
short, convex ; alveolar edge of both jaws with a deep groove : Chitra, 
Gray, p. 91 ; type Qymnopus lineatus (D. & B.) ; skull, figs. 11 & 12. 
C. The aberrant Mud-Tortoises^^ are now subdivided into 
three groups, each with one genus : — 
a. Skull short, depressed, flat above; palate flat, with scarcely any 
. alveolar ridges, and only a very slight pit before and behind the 
internal nostrils : Heptathyra (Cope), p. 93 ; type Cycloderma * 
frenatum (Peters) ; skull, figs. 13-15. Aspidochelys living stonii (Gray) 
is perhaps identical with the former species. 
b. Skull oblong, swollen, convex above; palate concave, with large, 
distinct alveolar plates, and a deep central pit before and behind the 
internal nostrils. Margin of the dorsal disk without internal bones ; 
Cyelanosteus, Gray, p. 94; type Emyda senegalensis (Gray); skull, 
figs. 16-21. 
c. The margin of the dorsal disk with internal bones; skull oblong, 
swollen, convex : Emyda, Gray, p. 97 type Testudo granosa, Schoeplf. 
Trionyx argus (Gray) proves to be identical with the North American 
Trionyx spiniferus (Lesueur) ; Gray, Proc. Zool. Soc. 1804, p. 89. 
New species : — 
Chitra indica. Dr. Gray (/. c. p. 89) shows that three species have been 
confounded under this name : one has the head short and is from Malacca ; it 
is figured by Gunther, as quoted above, and most probably identical with Tri- 
onyx bibronii (Owen) ; Gray names it Pelochelys cantoris. The second, Pelo- 
chelys cumingii, from the Philippine Islands, also has a sliort head. The third, 
for which Gray retains the name Chitra indica, has a long head, and is from 
the Gauges. 
* We do not see the reason why tliis name sliould be entirely suppressed. 
