318 Mr. W. E. de Winton on 
Colour of incisors orange above, honey-coloured below. 
The type is a somewhat young specimen, the skulls of 
older individuals reaching about 2 millim. more in total 
length. 
‘The nearest ally of this mouse is Mus erythroleucus, from 
West Africa; though outwardly differing in colour, the skull 
shows close affinities. 
There is one female in the collection, but unfortunately the 
mamme are not traceable; but, judging from the strong 
likeness in the skulls, there is little doubt that, like its ally, 
this new mouse is of the multimammate group. It will bear 
the name of the country in which it is found. 
9. Mus Jacksont, sp. n. 
Pelage composed solely of soft fur; the whole of the 
upper parts smoky brown, showing a little more golden on 
the cheeks and sides; underparts grey. All the hairs of 
the body are slate-coloured for the greater part of their 
length, only the extreme tips being coloured, those above with 
brown and those beneath with white. Ears dark, naked, and 
very long. ‘Tail much longer than the head and body, thin, 
naked, and unicoloured brown. Feet and hands very long, 
greyish. 
Measurements, taken from dried skin: type, ¢, Entebbi 
(Ntebe), 10. 2. 95:—Head and body 78 millim.; tail 118; 
hind foot 22; ear 14. 
Skull (base broken): point of nasals to lambda 22 millim. ; 
greatest breadth 11°5, of brain-case 11; nasals 9; basal 
length 22; henselion to hack of palate 11°5; palatal fora- 
mina 6x2; outside ™-! 6, inside ™-! 3; molar series 4°6; 
diastema 7. 
Molars large, all well developed, last two together fully as 
long as first. 
The length of the ears, tail, and hind feet at once distin- 
guishes this species from all its congeners; it is, indeed, both 
in colour and shape, strikingly like a diminutive Malacomys 
longipes, and I know no true Mus to which it is at all nearly 
allied. I name it in honour of the collector. 
It is highly probable that this mouse may prove to be iden- 
tical with Dr. Noack’s Mystromys longicaudatus (Zool. Jahrb. 
ii. p. 246, 1887), which belongs undoubtedly to the genus 
Mus, as is shown by the figures given of its skull and teeth. 
This being the case, the specific name need not be considered, 
as it is already occupied. 
10. Arvicanthis Speket, sp. n. 
In coloration and general pattern of the markings re- — 
