1864.] DR. J. E. GRAY ON THE TRIONYCHID. 85 
Trionyx cariniferus, spec. d & e, Cat. Shield Rept. B.M. 67. 
Hab. Amboina or Ceram (Madame Ida Pfeiffer). 
3. AspILus? ORNATUS. 
Trionyx ornatus, Gray, P. Z.S. 1861, p. 41, t.5; Ann. & Mag. 
N. Hist. 1860, vi. p. 218. 
* Trionyx javanicus, juv., Dum. & Bib.’ Mus. Paris. 
Hab. Camboja. 
Young specimens from Siam have rudimentary, narrow, linear, 
band-like callosities on the lateral sutures. Head minutely white- 
speckled (no large spot at angle) ; the first vertebral bone transverse, 
broad, with a prominence on the middle of hinder edge. The hinder 
part of the disk with close large tubercles. 
A stuffed young specimen from Sarawak, which appears to belong 
to the same species, has no indication of callosities. Head white- 
spotted, like young from Siam. The first vertebral bone separate, 
transverse, smooth, not rugose. The hinder part of the disk smooth, 
with a central elongated streak, and two oblique converging short 
lines of small tubercles. 
b. Lower jaw with a simple sharp shelving edge in front, and a flat 
shelving alveolar disk on the hinder half. 
* 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. 
PoTAMOCHELYS. 
Head elongate, rather depressed ; nose rounded ; forehead flat ; 
orbits submedial. Sternal callosities four. The palate of the skull 
rather convex behind, with a slight expansion on each side under the 
orbits, concave, contracted and bent down in front, with a short, very 
narrow, deep groove of equal width in front of the internal nostrils. 
The internal nostrils medial, large, oblong, hooded over by the di- 
lated side of the alveolar plates, and with a very long deep groove 
behind each of them. The alveolar surface of the upper jaw rather 
convex in front, shelving outwards behind, and with a raised inner 
edge, which hoods over the cavity of the internal nostrils. The 
lower jaw low and produced in front, with a simple sharp edge in 
front, and a subtrigonal, elongate, flattened, rather concave alveolar 
disk occupying the hinder half of the inner side. 
1. PoraMOCHELYS STELLATUS. (Skull, figs. 7, 8.) 
Trionyx javanicus, Geoff. Ann. Mus. xiv. 15, t. 3; Gray, Cat. 
Shield Rept. B. M. 67. 
Potamochelys javanicus, Fitz. 
T. stellatus, Geoff. Ann. Mus. xiv. 13 (junior). 
Hab. India: Deccan (Sykes). 
