According to Jerdon this vole has only been procured in Sikim near Darjeeling, at heights varying from 7000 to 15,000 feet; but I believe the area it inhabits to be much larger. Hodgson found his specimens at Darjeeling, and on one occasion got a nest in a hollow tree in the forest; it was saucer-shaped, of soft grass without any lining, and contained a male, female, and two young. The latter were "2-1/8 inches long, hairy above, nude below, and blind; the ears also closed." Jerdon writes: "Mr. Atkinson found it under fallen trees and stones on the top of Tonglo, near Darjeeling, 10,000 feet, whence also I had a specimen brought me."
The next species is one described and figured by Professor Milne-Edwards, and from Thibet he has two illustrations of it—one of an entire blackish-brown, the other darker above, but with the black belly.
[NO. 395. ARVICOLA MELANOGASTER.]
HABITAT.—Moupin in Tibet.
DESCRIPTION.—"It is characterised by the colour of the lower parts, which are a blackish-grey. The upper parts are sometimes as black as a mole, sometimes grizzled with brown" ('Mammifères,' p. 284). The brown specimen with the dark belly is evidently a rarity.
The members of this family are characterised by very large incisors; some have premolars, as in Bathyergus and two other genera, but not in the Spalacinæ, of which our bamboo-rat (Rhizomys) is the representative in India. "The grinding teeth are rooted, not tuberculate, but with re-entering enamel folds; infra-orbital opening moderate or small, with no perpendicular plate; occipital plane high, often sloped boldly forward; palate narrow; form cylindrical; eye and ear-conch very small, sometimes rudimentary; limbs short and stout; claws large; tail short or absent" (Alston, 'P. Z. S.' 1876, p. 86). There are two subfamilies—Spalacinæ and Bathyerginæ.
[GENUS RHIZOMYS—THE BAMBOO-RAT.]
"Form robust; eyes very small; ears very short, naked; pollex rudimentary; tail rather short, partially haired; skull broad; occipital plane only slightly sloped forward; infra-orbital opening small, sub-triangular; upper incisors arched forward; no premolar; upper molars with one deep internal and two or more external enamel-folds; the lower molars reversed."—Alston.
[NO. 396. RHIZOMYS BADIUS.]
The Chestnut Bamboo-Rat (Jerdon's No. 201).