112 
KAVIRONDO POTTO 
In the above connection attention is drawn to the following 
interesting letter which recently appeared in The Field. 
‘ The African Forest Fauna 
‘ Naturalists, and especially those who devote special atten- 
tion to geographical distribution, are accustomed to speak of 
a West African fauna as though it were distinct from that of 
all the rest of the continent. For many years past, however, 
evidence has been gradually accumulating to show that a large 
number of the genera of mammals long supposed to be peculiar 
to the West Coast and its hinterland really range right across 
the forest zone to the Semliki and Uganda, and the time has 
therefore come when our nomenclature should be changed. 
The immediate inducing reason for this change is, of course, 
the discovery and description of the potto ( Perodicticus ibeanus), 
and the consequent definite ratification of the evidence as to 
the occurrence of pottos on the eastern side of the continent. 
This discovery reduces the list of generic types of mammals 
peculiar to the West Coast to a very small number. One of the 
first types whose range was shown to include the eastern side 
of the forest region was the chimpanzee, which was recorded 
from the Niam-niam country by Schweinfurth, and later on 
from Monbuttu by Emin Pasha. On the other hand, the 
gorilla, the mandrill, and the drill still appear to be exclusively 
western types, although the possibility of their discovery in the 
east must not be overlooked. As regards other groups. Speci- 
mens brought home by Major Powell-Cotton proved the exis- 
tence in East Africa of the otter-shrew ( Potamogale ), the water 
chevrotain (Dorcatheriuin), and the red tiger-cafc ; while Mr. 
F. W. Isaac was the first to add the bongo ( Tragela'phus eury- 
ceros) to the eastern list, from skins and heads obtained by him 
from the Wandorobo. The yellow-backed duiker has been 
shown by others to extend to the Ituri and Rhodesia, and the 
royal antelope of Guinea is represented by a nearly allied 
pigmy species on the eastern side of the forest. The red Congo 
buffalo and the red river hog remain, it is true, distinctly 
western types ; but the former has an analogue in the Semliki 
Bos cottoni, of which females and immature males retain the 
ancestral red, the bush pigs of other species represent the red 
