26 EINAR LONNBERG, MAMMALS COLLECTED BY THE SWEDISH ZOOLOGICAL EXPEDITION ETC, 
in some instances be the remnants of such an invasion which have been able to 
survive in suitable localities. In other cases they may have come secondarily from 
the west. Considering the great desiccation which large tracts of Africa have been 
subjected to within the historic time or even up to the present time, — one need only 
to think about the gradual disappearance of Lake Ngami and the diminution of 
Lake Tsad — it appears quite possible, or even probable that East Africa for- 
merly has not suffered so much from drought as it does now. But if the climate 
has been somewhat more moist and the annual rainfall greater, the forests certainly 
would have extended and covered a greater area. This would have again, in a high 
degree, facilitated as well the survival of forest animals as even their distribution 
over a wider area than now. 
The minor subdivisions of the Western forest region according to R&rtcHENOW 
do not need to be repeated all here. It is sufficient for our purpose to mention 
the most eastern of them which may be called the Central Lake district. It extends 
over the countries round Albert Nyanza, Albert Edward Nyanza, and Lake Kiwu, 
the districts round Victoria Nyanza with the exception of its southern and south- 
eastern shores, and finally the countries bordering the northern part of Lake 
Tanganyika. 
Among the provinces of the Eastern Southern steppe region may be mentioned 
the »Northeastern» extending southward to Shoa and westward to Lake Tsad; the 
»Somali-Witu» district southwards to Tana river; »>German East Africa» southwards 
to Rufiji; thence come the »Nyasa» »Zambese» and »South African» districts, ete. 
To indicate the distribution of the animals collected or observed by this expe- 
dition the following letters have been used above. 
A = ranging all over the Ethiopian region. 
At = widely distributed across tropical Africa. 
E — East Africa s. str. that is German East Africa and the southern parts of 
British East Africa. 
Ea = all over, or at least over the greater part of the Eastern Southern steppe 
region. 
Eni = East Africa southwards to Nyasa land. 
Ez = East Africa southwards to Zambesi district. 
Es = East Africa to South Africa. 
Eno = East Africa and northwards beyond Somaliland. 
S = Somali district southwards to Tana. 
Se = Somalidistrict southwards to Kilimanjaro. 
Sno = Somalidistrict and northwards. 
W = West African forest region. 
We = Central Lake district of Western forest region. 
