434 Dr.J.E.Gray’s Synopsis of the Burrowing Squirrels 
Ill. Fur rather harsh, abundant ; sides with a narrow reddish 
streak. ‘ 
33. Macroxzus dimidiatus. 
Sciurus dimidiatus, Waterhouse, P.Z.S. 1840, p. 21; S. Baird, M.N.A. 283. 
Fur rather harsh, abundant, reddish iron-grey; hairs short, close, 
black at the base, with a broad pale-brown ring,a dark-brown sub- 
terminal ring, and a white tip; upper part of head, shoulders, legs, 
thighs, and feet, and a streak along each side of the body rufous; 
sides of the head, chin, and beneath yellow: tail reddish, black- 
varied; hairs reddish brown, with a broad black subterminal 
ring and reddish end, and grey base. 
Hab. South America? (Waterhouse’s type, not in a good 
state.) B.M. 
This specimen was purchased at a sale with some South- 
American squirrels; but it has much more the appearance of 
an African squirrel. No other specimen of this squirrel has 
occurred to me; so the true habitat is still doubtful. 
LI.—Synopsis of the Species of Burrowing Squirrels (Tamias) in 
the British Museum. By Dr. J. E. Gray, F.R.S., V.P.Z.S. 
Tae Ground-Squirrels form a very natural group, and are 
marked very similarly externally, so much so that it is very 
difficult to distinguish them from each other. But when you 
have a series of specimens from the same country, and from 
different localities, you can have no doubt that they are very 
distinct species, though it is very difficult to record the differ- 
ence in words; for no sooner do you think that you have hit 
upon a distinctive character that can be written down than you 
find it in some of the other specimens. 
The different species vary somewhat in size; but then the 
specimens from the same country vary a little in this respect ; 
yet there is an average size that is characteristic of the species. 
T. striatus of Europe and North Asia is the largest; and then 
follow J. Townsendu, T. americanus, then T. Hindsii and T. 
quadrimaculatus ; and T. quadrivittatus is the smallest. 
A. Tail as long as the body; back with five longitudinal equidis- 
tant black streaks, separated by four pale streaks; face with 
a white streak extended behind, above, and under the eye. 
a. The pale streaks wide, wider in the middle. Larger. 
Tamias striatus, Linn. 
Pale ash-grey, yellowish grey in the middle, grey on the sides. 
Hab. Europe: B.M. Asia, Altai: B.M. 
