[NO. 296. SCIURUS (RHINOSCIURUS) TUPAOIDES.]
The Long-nosed Squirrel.
HABITAT.—The Malayan peninsula and Borneo, and I believe the Tenasserim provinces.
DESCRIPTION.—This animal differs from all other squirrels by the extreme length of its pointed muzzle, with which is associated a long and narrow skull. The coloration varies from light to dark, and almost blackish-brown; the tail is shorter than the body, moderately bushy, narrow at the base, but expanding towards the tip; the hairs are broadly banded with four alternate pale and dark brown bands, the last being the darkest and broadest, with a pale tip; the under-parts are white in some, rich orange yellow in others.
SIZE.—Head and body, 7½ inches; tail reaches to the eye.
The Flying Squirrels next engage our attention. In several groups of animals of strictly arboreal habits, nature has gone beyond the ordinary limits of agility afforded by muscular limbs alone, and has supplemented those limbs with elastic membranes which act like a parachute when the animal takes a leap into space, and gives it a gradual and easy descent. Amongst the lemurs the Galeopithecus, the Pteromys in the squirrels, and the Anomalurus in another family of rodents, are all thus provided with the apparatus necessary to enable them to float awhile in the air, for flying is scarcely the proper term for the letting-down easy principle of the mechanism in question.
The flying squirrels, with which we have now to deal, are in general details the same as ordinary squirrels, but the skin of the flanks is extended between the fore and hind limbs, which, when spread out, stretches it into a wide parachute, increased in front by means of a bony spur which projects from the wrist. These animals have been subdivided into the large round-tailed flying squirrels, Pteromys, and the small flat-tailed flying squirrels, Sciuropterus. The distinction was primarily made by F. Cuvier on the character of the teeth, as he considered Sciuropterus to have a less complex system of folds in the enamel of the molars, more like the ordinary squirrels than Pteromys; but modern research has proved that this is not a good ground for distinction. Dr. Anderson has lately examined the dentition in eleven species of Pteromys and Sciuropterus, and he says: "According to my observations the form of the enamel folds in youth are essentially similar, consisting of a series of tubercular folds which are marked with wavy lines in some, and are smooth in others, but in all there is a marked conformity to a common type. The seemingly more complex character of the folds appears to depend on the extent to which the tubercular ridges are worn by use." He also questions the propriety of the separation according to the distichous arrangement of the hairs of the tail. After a careful examination of the organ in nearly all the members of the series, he writes: "I have failed to detect that it is essentially distinctive of them—that is, that the distichous arrangement of the hairs is always associated with a diminutive species; but at the same time there can be no doubt that it is more prevalent among such." He then goes on to show that the tail is bushy in seventeen species, partially distichous in one, and wholly so in ten, and concludes by saying: "I am therefore disposed to regard the flying squirrels generally as constituting a well-defined generic group, the parallel of the genus Sciurus, which consists of an extensive series of specific forms distinguished by a remarkable uniformity of structure, both in their skulls and skeletons, and in the formations of their soft parts." There is a laudable tendency nowadays amongst mammalogists to reduce as far as possible the number of genera and species, and, acting on this principle, I will follow Dr. Anderson, and treat all the Indian flying squirrels under Pteromys.
General anatomy that of the squirrel, except that the skin of the flanks is extended between the limbs in such a manner as to form a parachute when the fore and hind legs are stretched out in the act of springing from tree to tree.
[NO. 297. PTEROMYS ORAL.]
The Brown Flying Squirrel
(Pteromys petaurista in Jerdon, No. 160).
NATIVE NAMES.—Oral of the Coles; Pakya, Mahrathi; Parachatea, Malabarese; Egala dandoleyna, Singhalese.