634 REPORT OF THE HARVARD AFRICAN EXPEDITION 
The report also makes a study of the geographical distribution of the gorilla 
(see Map VIII). 
The gorillas of Africa are found in two limited equatorial regions, separated 
by a section of the Upper Congo basin that extends from 16° east to 29° 45’ east. 
The greater part of this intermediate region is covered with dense equatorial 
forest and, with the exception of three skulls reported as found in a native hut 
near Bondo, 23° 50’ east on the Uele River, we have no authentic evidence that 
gorillas exist there. The skulls referred to are similar to those of the Cameroons 
and might well have been carried over by natives. For convenience in distin- 
guishing the two groups, I shall again refer to the western ones as the Coast 
gorillas, even though most of them live at some distance from the Atlantic and 
some inhabit a mountainous region. The eastern ones are largely found in the 
highlands of the eastern Congo and will be called the Mountain gorilla (although 
my friend, Major Collins, shot one at an altitude of a little over two thousand 
feet near Walikale). 
The distribution of the two groups can be seen by referring to the accompany- 
ing map. 
The limits of the range of the animal on the coast have been determined 
largely by plotting in all the places whence skulls that seem reliably labelled have 
come, and by outlining this area. 
For the Coast gorilla, the westernmost boundary approximates the Cross 
River in the southern provinces of Nigeria. The most westerly point actually 
recorded is Ikom, 8° 40’ east and 6° north. The northernmost point is close to 
Basho, 9° 25’ east, 6° 7’ north. On the east we have reports from several places 
such as Wesso and Nola on the Sanaga River. The Sanaga River, about 16° 15’, 
seems to mark the eastern boundary of the range of the Coast gorilla. On the 
southeast the line follows the border of the forest which reaches its southernmost 
limit at Mayombe on the edge of the Belgian Congo, 5° south, 13’ east. Along 
the Atlantic coast in most places the forest begins a little way inland. Gorillas 
have been reported actually on the coast, but generally they are found not closer 
than thirty miles from the sea. They seem especially plentiful along the Gaboon, 
Ogowe, Camp, and Sanaga rivers. 
The Mountain gorilla is found in a comparatively narrow strip of the east- 
ern Congo. Its principal habitat is the mountain forest as distinguished from the 
lowland forest of the Belgian Congo. Its northern limit is Mulu, 0° 10’ south, 
29° 10’ east (Absil and Chapin). We find it as far west as Walikale, 1° 20’ south, 
28° 1’ east, where it strays a little into the lowland forest. The eastern limit 
seems to be close to Kigezi in Uganda, 1° 15’ south, 29° 45’ east. The southern 
limit is Baraka on Lake Tanganyika, 4° 19’ south, 29° 2’ east. In this entire 
region the gorillas that are most known and accessible are the troops that inhabit 
the voleano regions where Akeley died while studying them. Whether they are 
entirely isolated from contact with outside gorillas at the present time is doubt- 
ful and has not yet been established. In the mountains back of Baraka, 
Boko, Uvira, and Katana large troops have been recently found in the upland 
forests. 
