There is some confusion between this and the next species, S. lokroides, and the distinctive characteristics quoted by Jerdon and others, founded on colouring alone, are not to be depended upon, for colouring varies, but there is considerable difference in the skulls of the two, S. lokriah having a smaller skull, with distinct peculiarities. The inter-orbital portion of the skull is narrower anteriorly and posteriorly, and the muzzle is narrow at the base, and of nearly equal breadth throughout. The nasals are long and narrow, and reach further back than in S. lokroides. These points, which are brought forward by Dr. Anderson, are sufficient to indicate that they are quite distinct species. As regards colouring S. lokriah has normally red thighs, but even this is absent at times. Dr. Anderson says: "It is much more richly coloured than S. lokroides, with no rufous even on the thighs, and with generally a tuft of pure white hair behind the ear, by which it can be recognised, as it occurs in twenty instances out of twenty-five, and even when absent the hairs in that locality have a paler colour. As this whitish tuft lies backwards, it is only seen when the ear is carefully examined."
[NO. 278. SCIURUS LOKROIDES.]
The Hoary-bellied Grey Squirrel (Jerdon's No. 154).
HABITAT.—In the lower ranges of the South-eastern Himalayas, Nepal, Sikim, Assam, Tipperah and Arakan.
DESCRIPTION.—This is a most difficult species to describe. Dr. Anderson writes: "I have before me sixty-two examples of various squirrels which have been referred to S. lokroides, S. Assamensis and S. Blythii by Hodgson, M'Clelland and Tytler, also the types of S. similis (Gray), which were forwarded to the British Museum as S. lokroides by Hodgson. After a careful consideration of these materials, they appear to me to be referable to one species. Hodgson, who first described it, referred to it all those Himalayan squirrels slightly larger than S. lokriah, and which had the ventral surface either pale whitish or slightly washed with rufous, the sides also being sometimes suffused with this tinge especially on the anterior half of the thigh, which in many is bright orange red; but this colour is variable, and many squirrels have this portion of the body white, of which S. Blythii is an example; and others similar to it are before me from Bhutan and Assam which do not differ from S. lokroides except in the presence of this white area, which is evidently only a variation on the red area, and probably a seasonal change, as many show merely a faint rufous tinge in the inguinal region, that colour being entirely absent on the outside of the thigh.
"It is, however, worthy of note that those squirrels which have a rufous tinge in the inguinal region rarely, if ever, have the outside of the thigh bright red, and that the squirrels distinguished by white on their thighs are from Bhutan, Assam, and the Garo hills. But I do not see that these latter differ in any other respect from the squirrels sent by Hodgson as specimens of S. lokroides, with and without red thighs. Moreover, one of Hodgson's specimens of S. lokroides shows a tendency in the thigh to become white" ('Anat. and Zool. Researches,' pp. 247, 248).
The difficulty in laying down precise rules for colouring is here evident, but in general I may say that the upper parts are rufescent olive brown, the hair being grizzled or banded black and yellow, commencing with greyish-black at the base, then yellow, black, yellow with a dark brown or black tip; the lower parts are rufous hoary or grey, tinged with rufous, or the latter shade may be restricted to the groin or inguinal parts. The fur is coarser and more broadly ringed than in S. lokriah, and the ventral surface is never tinged with orange, as in that species; the tail is concolorous with the back; the hair more coarsely annulated; there is no white tuft behind the ears, as in the last species.
SIZE.—About the same as the last, or Dr. Anderson says: "In the form referable to S. Blythii, a white spot occurs on the inguinal region of the thigh in the position in which the rufous of the so-called red-legged squirrels is developed. The groin in some of these squirrels shows also a decided rufous tinge, while the remainder of the belly is sullied grey white. If these forms were without the white thigh-spot, they would exactly conform to the type of S. Assamensis. A squirrel in the British Museum, labelled S. Tytleri (Verreau, 'Indes Orientales'), agrees with S. Blythii" ('A. and Z. Res.', p. 249).
Blyth has seen a squirrel of this species renewing its coat, and assuming a variegated appearance during its transition to the breeding dress.
A jet-black squirrel of the same proportion occurs in Sylhet and Cachar, which Dr. Anderson is inclined to think belongs also to this species.
We may, therefore, regard the following as being the same as S. lokroides, viz., S. Assamensis, S. Blythii, S. similis, and the black one, which has apparently not been named.