scales. Head, in life, leaden; iris brown; neck and skin of limbs pale yellowish-
brown. Large scales on the limbs blackish, with brownish margins.
Inches.
Total length of carapace . . . . . . . . . I • • •
„ of sternum . . . . . . . . • • 8’10
Axillaiy breadth . . . • • • • ' • •
Inguinal „ • . . • • • .. . . . . 6-70
Breadth greatest over curve . . . • . • • • . 8'60
Depth through s k u l l ........................................................................, • , • S'OO
The only locality from whence I have obtained examples of this interesting
species was the hilly region in the neighbourhood of Akyab in Arracan.
Genus E m y s , Cuvier.
I t is being gradually discovered as naturalists look to the structure of the animals
which have been referred to the genus Emys, that it includes many forms
which cannot be regarded as generically identical. So little, however, is yet known
of the structure and real affinities of the animals comprising it, and of their relations
to each other, that any attempt to group the animals into genera, based on present
knowledge, must be essentially tentative. Dr. Gray, who has contributed much
to our knowledge of the Chelonia, in describing the species in the British Mu,
seum in 1855, referred 83 species to the genus Emys; but in 1870, after a consideration
of more ample materials, and chiefly of the skull characters, referred the
33 species to no less than 12 distinct genera, some of which axe undoubtedly well
marked generic types of structure, the features of which are especially pronounced
in the modifications which take place in the skull, more particularly in the
character of the fronto-nasal region, the zygomatic arch, and the alveolar surface
of the jaws and palate. Such modifications are generally found extending to a
number of species, but the differential features are occasionally masked by similarity
in the outward form. On the other hand, species which by external appearance
would be thought widely apart are found, on close examination and on reference
to the internal structure of the shell and skull, to be very closely allied, e. g., the
two sub-genera MCorenia and ELardella among the EataguridcB. These two sub-
genera, however, are placed by Strauch widely apart, Morenia ocellata being grouped
next to Pangshura smithi, and Eardella thurgi close to Emys trijuga, with which
it baa no more affinity than Morenia ocellata has with Pangshura smithi. The
forms referred to Emys, by Strauch, also present a remarkable diversity of structure,
as is seen in the two species Pyxidea mouhotti and Cyclemys orbiculata, Bell,
the latter of which possesses cloaca! bladders and a broad palate like Geoemyda,
whereas Pyxidea mouhotti has no cloacal bladders, and has a narrow palate like
Emys, with. a feeble zygomatic arch, a character which also occurs in the skull of
Cyclemys, and in some of the North American forms referred to Cistudo.
Dr. Gray referred1 the Emydida to three types of structure, the Geoenvy dina,
Emydina, and Belliana, the first typified by the genus Geoemyda, the second by the
1 Suppl. Cat. Shd. Sept., 1870, p. 25.
genus Melanochelys, and the third by the genus JBellia. The first two of these,
according to Gray, contained forms with imperfect, or perfect zygomatic arches.
The first, he stated, had never webbed feet, the second had webbed feet, and the
third tribe, Belliana, resembled the Emydina. The only one genus, however,
among the 15 genera referred to those tribes that possesses an imperfect zygomatic
arch is the genus Geoemyda. Although Gray stated that Melanochelys had an imperfect
and weak zygomatic arch, this was an error, as the species E. trijuga, on
which the genus is founded, has been satisfactorily proved by my personal observation
of many skulls from Ceylon, Southern India, Madras, Central India, and
Burma, to have a perfect zygomatic arch, so that the genera of the second and
third groups are all distinguished by a perfect arch. I t is doubtful whether
several of the nine genera, referred to the Emydma, may not have ultimately to
be united with the genus Emys, which I temporarily accept in the sense adopted
by Gray, with the above correction.
E m y s t r i j u g a , D. & B., var. burmana. Plate LYII & LYIII.
Emys trijuga, Theobald, Joum. Linn. Soc., vol. x, p. 18, 1868 (pars).
Emys edeniana, Theobald, Descr. Cat. Rept., Brit. Ind., 1876, p. 12.
Shell not so elongately oval as in Indian examples of the species, moderately high
and broad, and broader in females than males, anterior margin slightly posteriorly
concave. Lateral margin acutely revolute in the young, reduced to a ridge in
nearly adult specimens. In the young slightly expanded at the eighth marginal,
the posterior marginal shields being involute, more so in some than in others,
and feebly in the adult. The posterior margin is slightly serrated in some
young specimens and undulating in adults; caudal notch hardly developed. Three
dorsal ridges, the vertebral ridge the most prominent; the costal areolar ridges
very feebly developed, passing through the areolae which have sometimes a tendency
to nodosity, and not extending on to the last costal and scarcely on to
the first, in which, however, the areolae are well marked. The costal ridges
nearly disappear with age, but the vertebral is always distinct, and most prominent
on the three last, and on the first vertebral. The nuchal is narrow and almost linear
broader behind than in front. The vertebráis are generally broader than long, the
second and third being as long as broad. There are frequent exceptions to this,
especially in the case of the first vertebral which is often much longer than broad,
and in such cases the other vertebráis partake of its elongated character. All the vertebráis,
with the exception of the first and last, are almost as broad in front as behind,
and the costal margins of the second, third and fourth are all about one length, the
anterior costal margin of each being more or less convex, and the posterior concave.
The first vertebral is pentagonal, either broader than long, as long as broad, or considerably
longer than broad. Its lateral margins are more or less concave in the
middle, but divergent anteriorly. The posterior margin is transverse, notched for
the vertebral ridge. The second vertebral is generally a little broader in front than