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APPENDIX B 
within the dense forest. Evidently very abundant in the forest, but not ventur¬ 
ing at all into the open. Strictly nocturnal. Dwell under logs and in decayed 
places around stumps, and the trunks of big trees. 
Epimys panya (East African House Mouse). Common in B. E. A., coming into 
the houses, and acting like a house mouse, but twice the size. Frequently came 
into our camps, entering the tents. Very common on the edges of the forest 
and in brush country and long grass, and among the shambas; not in the deep 
forests, except along streams, and not in the bare open plains. Nocturnal. 
Found in the runways of Otomys and Arvicanihis. Does not seem to be a 
grass-feeding species, like Otomys; eats grain, beans, etc. 
Epimys nieventris ulae (Athi Rock Mouse). On the Athi Plains, in the Sotik, around 
Naivasha, and in the Rift Valley. Body only slightly larger than that of a 
house mouse, but tail at least a third longer than the head and body together. 
Yellowish-brown above and whitish beneath. Never found except among 
rocks; we always found it where there were cliffs or on stony koppies. Lives 
in crevices in the rocks and along the ledges of the cliffs. Nocturnal. Caught 
in traps with nuts. 
Zeloiomys hildegardcB (Broad-headed Bush Mouse). Looks like a small-eared, 
broad-headed house mouse. Rather common on Athi Plains, in same localities 
with Uganda mouse, but rarer, and seldom enters houses. 
Thamnomys surdaster polionops (Longtailed Tree Mouse). Arboreal; more like a 
mouse than a rat. On the Athi Plains, in the Sotik and Rift Valley. Not 
found in heavy forest, but in the open acacia woods and in bushy country. 
Apparently lives much of the time on the ground, and builds no nests in the 
trees, but runs up and down them and among their branches freely. Nocturnal. 
Thamnomys Loringi Heller (n. s.) (Masked Tree Rat). In the Rift Valley; common 
around Naivasha. Has a black ring around each eye, the color spreading over 
the nose like a mask. Arboreal and nocturnal. Much the habits of our neo- 
toma, but do not build large nests. Build nests about six inches in diameter, 
made of sticks, placed in the branches of the thorn-trees; also in burrows near 
the bottom of the trunks; runways lead from the trees containing the nests 
to the burrows. Trapped on the ground and in traps set in notches of the trees. 
Oenomys hypoxanthus bacchante (Rusty-nosed Rat). Found in same country as 
above, and with similar habits, but somewhat less arboreal. A handsome species. 
Dasymus helukus Heller (n. s.) (Swamp Rat). In appearance much like the Alex¬ 
andrian or roof rat, but with longer hair and shorter, much less conspicuous 
ears. Found all over the Athi Plains where there was brush, especially along 
stream beds. Nocturnal. 
Arvicanihis ahyssinicus nairohce (Athi Grass Rat). The commonest mouse in B. 
E. A. on the plains. Outnumbers any other species. Found everywhere in 
grass and brush, but not in deep forest. Often lives in shallow burrows round 
the bases of thorn-trees, from which its well-marked runways radiate into the 
grass. Strictly diurnal. Often seen running about in bright sunlight. Never 
found in traps at night. A striped mouse that has lost its stripes, vestiges of 
which are occasionally found in the young. 
Arvicanihis pulchellus masaicus (Nairobi Striped Mouse). Diurnal. Common on 
the Athi Plains and on the Sotik and in Rift Valley. Around Neri we often saw 
them running about through the shambas. Live in brush and cultivated fields. 
In pattern of coloration much like our thirteen-striped gopher. 
