'The Expedition for the survey of the rivers Euphrates and Tigris, carried on by order of the British government, in the years 1835, 1836, and 1837; preceded by geographical and historical notices of the regions situated between the rivers Nile and Indus. In four volumes. With fourteen maps and charts, and embellished with ninety-seven plates, besides numerous wood-cuts. Volume the first.' [‎734] (834/905)

734
APPENDIX.
part of the carapace, are not alluded to in the account of G. JEgyptiacus;
they are, however, very conspicuous in the animal in question. There are, it
may be added, no pellucid scales, placed in a transverse direction, on the
under surface of each elbow, nor are there any depressed convex tubercles,
either anteriorly or posteriorly, on the cartilaginous expansion of the cara
pace, as are often, though not invariably, found in the G. JEgyptiacus.
With respect to the Gymnopus Euphraticus (Trionyx Euphraticus)
originally described by Olivier (Voyage en Perse, torn. iii. p. 453, tab. 41),
the carapace is described as being broader behind and before, which, it
reference be intended only to the osseous disc, is not the case in the present
animal. As in that species, however, the circumference of the carapace is
smooth, and the skin is folded at the elbow-joint, above, but does not simulate
scales. The circumstance of a mesial depression, or, rather, double channel,
with a convex line between, down the vertebral column, is not noticed as
characteristic of the G. Euphraticus, nor are the smooth anterior oval fovese.
Still, however, it is not improbable that the animal in question may be iden
tical with that described by Olivier; but it remains to be seen whether his
species be distinct from G. JEgyptiacus, a point which his short and imperfect
account does not enable us to solve.
2. Gymnopus (undetermined).
3. Agama mutahilis.
4. Scincus cupreus.
5. Coluber Cliff or dii.
6. Coluber Chesneii (Martin).
This last species is allied to Col. Hippocrepis, but differs in the shape of the
muzzle (which is more acute), in the figure and extent of the nasal and labial
plates, and in the disposition of the markings.
The labial plates are small and numerous, and in one specimen several are
divided.
The posterior frontals are small, and in one specimen are divided into two.
The anterior frontals are contracted.
The superciliary plates are convex; the eyes are small.
The scales of the trunk are small, imbricate, and without a keel.
The head is pale yellowish brown, the plates beautifully freckled, or finely
marbled with dark brown; a brown band traverses the superciliary and
verticle plates from eye to eye, and then descends on each side obliquely to
the angle of the mouth. The labial plates are bordered with dusky brown,
or deep gray.
The ground colour of the body above is yellowish brown; a series of
square spots of a brown, or olive-brown colour, extend from the back of the
neck, above the median dorsal line, to the end of the tail. On the sides of the
neck begins a line of the same colour, which soon breaks into elongated
narrow marks, which, towards the middle of the body, become confused,
broken, and irregular.