GERBILLUS PYEAMIDUM. 
255 
Gekbillus PYEAMIDUM, GeofFr. (Plate XLI.) 
Gerbillus pyramidurriy Is. Geoffr. Diet. Class. H. N. vii. 1825, p. 321; F. Cuv. Trans. Zool. Soc. ii. 
1838, p. 141, pi. XXV. figs. 6-9; et auct. 
7. Abu Roash. 
5. Pyramids o£ Gizeh. In alcohol. 
4. Gizeh. Capt. S. S. Flower. Skins. 
? . Tel el Amarna. Dr. Flinders Petrie. In alcohol. , 
14. Near Cairo. Dr. C. W. Andrews. Skins. 
The proportions of the distance between the ear and the eye, and between the latter 
and the end of the snout, are much the same as in the previous species. The ear 
is of moderate size, but not quite so rounded at the tip as in G. gerhillus, the 
posterior margin being feebly concave towards the tip. When laid forward, the ear 
reaches to near the anterior angle of the eye, so that in this respect the two species 
are alike. The proportions of the forearm and hand to the length of the tarsus and 
foot are the same as in G. gerhillus^ as are also the proportions of the fingers and 
the structure of the palm, but the palmar cushions and the under surfaces of the 
fingers are more sparsely covered with hair. The structure of the hind foot is the same 
as in the previous species, and also the proportions of the toes, and the third and fourth 
toes are liable to the same variation in their length, either one being occasionally longer 
than the other, or the two may be of the same length. It is, however, distinguished 
by the more nude character of the sole of the foot as compared with G. gerhillus. Its 
tail, also, has the same structural character as that of G. gerhillus, and the hairs on 
it have a similar distribution. The snout and ears, as regards the extent to which 
they are covered with hair, are the same in both species, but the ears of G. pyramidum, 
instead of being white, have their tips and external margins dusky. Some of the 
moustachial hairs are black, and are usually not so long as in G. gerhillus. 
The general colour of the upper parts is a rich fawn on the sides, washed with 
blackish on the top of the head and back, owing to the hairs on those parts being 
tipped with black. There is no white spot before the eye, but there are pale spots above, 
below, and behind it, and some of the hairs behind the ear are white. The eyelids 
and the area around the eyes and a narrow line descending obliquely downwards from 
the eye are more or less dusky black. The under surface is pure white, or with an 
admixture of yellowish, and in some specimens there are feeble traces of fawn-coloured 
spots. The upper surfaces of the fore and hind feet are clad with short white hairs, 
much the same as in G. gerhillus, and the upper surface of the tail is concolorous with 
the back, the under surface paler or sometimes nearly white; the long hairs near the 
end being distributed as in the foregoing form, but darker in colour. 
