KUNGL. SV. VET. AKADEMIBNS HANDLINGAE. BAND 48. N:0 5. 25 



and. Sahara where the animal life is different, and in some respects more similar to 

 that of East Africa, at the same time as endemic forms are to be found there. 



The Somali district is, however, as fully entitled to be regarded as an inde- 

 pendent zoogeographical district as South Africa, but both show great affinities with 

 East Africa. 



It appears therefore better to accept also for the mammals the same system 

 for the zoogeographical subdivision of the Ethiopian continent as Reichenow has 

 used for the birds in his great work »die Vogel Afrikas*.^ The author quoted divides 

 Africa in a Western forest region and an Eastern Southern steppe region. This 

 system is, of course, in the same way as its forerunners based on the biological con- 

 ditions which are the results of the topographical, meteorologial and climatological 

 factors which have made the forest dominating in one, steppe (and thornbush) in 

 another part of the continent. These two main regions are afterwards subdivided 

 in a number of smaller zoogeographical provinces and these constitute, so to say, 

 smaller zoogeographical centres, or in some cases transition tracts with a mixed fauna. 

 There is evidently no sharp boundary lines between these minor provinces, some of 

 which will be mentioned below, and not even always or in every respect between the 

 main regions. This can the less be the case as the types of landscape and the upon 

 the same depending biological conditions are not completely uniform. There are 

 thus to be found broad open tracts of land within the forest region, and patches of 

 forest scattered in the steppe region with the consequences with regard to the fauna 

 which have been set forth above. 



It must also in this connection be remembered that the occurrence of the dif- 

 ferent species of mammals in different localities of Africa in the present time is not 

 only the result of the present possibilities for distribution to this or that loca- 

 lity, but it is in many cases depending upon the possibility to survive which 

 the locality in question has been able to offer certain animals. Paleontological facts 

 indicate that the ancestors of a great number of the present Ethiopian mammals 

 have invaded the continent from the northeast and east during the Miocene and 

 Pliocene. It is also wellknown that several mammals which now inhabit Western 

 Africa have their nearest relatives in the Oriental region. For instance: 



Perodictius Nycticebus 



Poiana Linsanga 



Nandinia Paradoxurus 



Dorcatherium etc. Tragulus etc. 



The ancestors of the, in present time. West African mammals which invaded 

 the continent from the northeast must thus evidently have passed through the coun- 

 try which is termed East Africa nowadays, and for some time lived there. If such 

 mammals still should be represented in East Africa, these representatives may perhaps 



1 Berlin 1900—1901. 



K. Sv. Tet. Aiad. Handl. Band 48. N:o 5. 4 



