THE SPINY MICE OF BRITISH EAST AFRICA 58 
6. Acomys nubilus, Dollm., is known only from the 
specimens collected by Mr. Percival at Magadi. 
7. Acomys Wilsoni, Thos., originally described from 
Mombasa, has since been collected at Kitui, Voi, Taveta, 
Teita Hills, Tsavo River, Yata Plains, Mazeras, Taru Desert, 
Sagala, and the Witu Forest. 
8. Acomys W. abilities, Dollm., a close ally of the above, 
was founded on a series of specimens obtained by Mr. Kemp 
at Nyama Nyango, on the Northern Guaso Nyiro. 
These eight forms may be arranged for identification as 
follows : — 
A. Tail long, more than 75 mm. in length. 
a. Size of body large (head and body about 
100 mm. in length), 
a'. Colour of dorsal surface bright 
orange-rufous .... ignitus 
b'. Colour of dorsal surface pale grey- 
ish sandy buff . . . .4. Kempi. 
c'. Colour of dorsal surface vinaceous 
drab . . . . . i. montanus. 
b. Size of body smaller (head and body 
about 90 mm. in length), 
a'. Dorsal surface pale greyish buff ; 
underparts pure white. Spines 
slender ..... 'pulchellus . 
fo\ Dorsal surface slate-grey ; under- 
parts dirty grey, never pure white. 
Spines coarse .... Percivali. 
B. Tail short, never more than 70 mm. in length 
a. Tail more than 60 mm. in length (average 
length 66). General colour of 
back dark sepia-brown . . nubilus. 
b. Tail less than 60 mm. in length (average 
length 50 mm.) 
a'. General colour bright rufous- orange 
speckled with brown . . . Wilsoni. 
b'. General colour drab-brown, speckled 
with pale buff. Size rather smaller W. ablutus . 
