During a long sojourn in the easternmost parts of Belgian Congo Captain Elias Arr- 

 henius has collected the extremely valuable material of mammals on which this 

 memoir is based, and at his return home he most generously pesented the same to the 

 R. Swedish Natural History Museum. For this magnificent gift I beg to publicly express 

 my great gratitude on behalf of the Museum. 



The localities at which Captain Arrhenius has collected this material are the 

 following: 



Rut s huru: the station itself is situated a little to the east (perhaps about 12 

 km. to judge from a map) of Rutshuru River, about half way between Lake Albert Ed- 

 ward and Lake Kivu. There are partly open plains, but also forests on mountains. Such 

 a mountain forest, in which Chimpanzees were collected, is situated aboutöhours march 

 from Rutshuru station. Another forest is mentioned in the diary with the following 

 words: »la Shasha-riviére — petit forét». Colobus occidentalis was found there. An- 

 other forest, in which Duikers, Baboons and Leopards were obtained, is mentioned as 

 »montagne et forét Kabwe». 



Kasindi near the northern end of Lake Albert Edward. 



Beni: the station is situated about 60 km. north of the shore of Lake Albert 

 Edward and surrounded by the great forest. Very many forest animals of diff erent kinds 

 were collected here, some of them at a distance of a couple of days march to the west 

 of Beni. 



The volcano Mikeno among the Virunga mountains about 30 km. north east 

 from Kissenji which is situated at the northeastern shore of Lake Kivu. In the bam- 

 boo-forest of Mikeno Gorillas were collected. 



Mas is i: a station situated not far from Lake Kivu. At this place many forest- 

 animals as Monkeys, Squirrels, Duikers etc. were collected. 



All these localities are situated in the Central African Lake District, or on the fron- 

 tier to the great West African Forest-region. In consequence of this it must be expected 

 from a zoogeographical point of view that the greatest number of the mammals from 

 these localities ought to belong to the West African fauna, or at least to be so to say of 

 western type and have their nearest relatives in West-Africa. This is also the case. 

 There are, however, as can be seen from the list below, also certain mammals representing 

 species which are pretty evenly distributed över the greater part of the African continent, 

 even if they have developed a greater or less number of subspecies. The presence of such 

 mammals in a district does not give the fauna any certain zoogeographical stamp in the 



