Small Mammals from the Upper Nile. 27d 
On a closer examination I find that the Aden Arvicanthis 
referred by me to A. variegatus* is really quite indistin- 
guishable from A. testicularis. This is a striking example 
of the general relationship of Aden animals to Soudanese and 
Abyssinian, rather than to Egyptian forms. 
10. Arvicanthis zebra, Heugl. 
6. Fashoda. 2nd April. 
The posterior back of this mouse is not so rusty as is 
stated in the original description, but otherwise it agrees 
fairly well, and may be provisionally referred to Heuglin’s 
species. 
11. Gerbdillus + sttymonyx luteolus, subsp. n. 
dg. Duem. 23rd May. 
Type. B.Mi. no. I. 8.8. 27. 
* P.Z.S. 1895, p. 553. 
+ I may take this opportunity to describe 
Gerbillus (Dipodillus) Harwoodi, sp. n. 
A member of the G. campestris group, hitherto unrecorded in East 
Africa. 
General colour dark fulyous, decidedly darker along the dorsal area, 
brighter and richer along the flanks, where it forms a bright fulvous line 
sharply contrasting with the white of the belly. Under surface pure 
white throughout, the hairs white to their bases. Crown of head like 
back; cheeks paler fulvous; postocular light marking indistinct, post- 
auricular well defined. Ears small, their hairs dull fulvous. Front of 
fore imbs like body, inner side and upper surface of hands pure white. 
Outer side of hind limbs like body, but the ankles are darker and more 
mixed with slaty ; inner sides and whole of feet white. Soles almost 
naked, a few scattered hairs present in the region of the pads, which are, 
as usual, six in number. ‘Tail long, well haired, but little tufted; brown 
above and terminally, whitish proximally below. 
Skull of the general shape characteristic of the G. campestris group. 
Dimensions of the type (an adult female, measured in the flesh) :— 
Head and body 82 millim.; tail 113; hind foot 22; ear 10. 
Skull: greatest length 26; basilar length 19; length of nasals 10; 
interorbital breadth 4:5; parietal breadth 12; interparietal 32x66; 
diastema 6°5; palatal foramina 5; length of upper molar series 3°6. 
Hab. Lake Naivasha, British East Africa. Altitude 6300 feet. 
Type. Female. B.M.no.0. 6.21.17. Original number 12. Collected 
15th December, 1899, and presented by Lord Delamere. 
So far as | am aware no member of this group has hitherto been 
described from the EKast-African region, all the known forms being either 
large gerbilles of the subgenus Yatera or else pigmy forms allied to 
G. pusillus, Peters. 
I have named this pretty species after Mr. L. C. Harwood, the taxi- 
dermist who accompanied Lord Delamere and prepared the specimens, 
Mr. Harwood has been ona great number of East- and West-African 
collecting expeditions, and to his abilities much of the success of these 
expeditions has been due, at least so far as mammals and birds are 
concerned. 
