No. 14. — New African Rodents. 

 By Glover M. Allen. 



In a previous paper (Bull. M. C. Z., 1911, 54, p. 321-331) I have 

 reported on the bats collected in British East Africa during the sum- 

 mer of 1909 by Dr. William Lord Smith, Mr. Gorham Brooks, and 

 myself. In working out the other small mammals obtained by our 

 expedition, several unnamed forms have been found and these, as 

 well as a dormouse from the Cameroon, presented by Dr. Thomas 

 Barbour, are described as new. The new mammals obtained in 

 East Africa are all from the northern Guaso Nyiro, northwest of Mt. 

 Kenia, where as a result of the arid plateau conditions many of the 

 species are represented by local forms of less intense coloration than 

 their relatives of the coastal lowlands. A number of these have 

 already been described by Thomas, Dollman, and others. 



The recent intensive study of the small mammals of Africa has 

 shown not only a surprising wealth of species but also an immense 

 amount of local varieties of these, which are the result of response to 

 the greatly diversified physical conditions. This was strongly im- 

 pressed upon us even in the comparatively short circuit covered to 

 the north and west of Mt. Kenia, and thence to Nairobi and the coast. 

 Dry rocky and bushy country succeeds fertile and well watered low- 

 land, papyrus swamp gives place to broad flat plains, well grassed 

 perhaps, or again, arid and grown up with xerophytic vegetation, 

 according to the character of the soil. Crossing a divide brings one 

 into deep wet forests whose stillness awes even the lightsome Swahili 

 porters into silence, while the higher mountain peaks even under the 

 equator reach an altitude of everlasting snow with alpine meadows 

 below their glaciers. Each variety of country has its characteristic 

 set of inhabitants and these again differ locally. 



Among the species here described, the most interesting is perhaps 

 a naked burrowing rodent of the genus Heterocephalus, hitherto 

 unrecorded outside of Abyssinia and Somaliland. It is another of 

 those northeastern types that find their southwestern limits along 

 the Guaso Nyiro. From this locality also, a dormouse (Graphiurus) 

 is apparently for the first time recorded. It seems to be a local race 

 confined to the scanty tree growth which forms a narrow border 

 along the streams. The dark colored, small eared pygmy dormouse 

 from the Cameroon is also of unusual interest. 



