ol4 Bulletin American Museum of Natural History [Vol. LIII 
Nyasa with a total of 361 and 86 endemics coming second. Victoria 
Nyanza has a somewhat smaller total, viz. 289, but a larger number of 
endemic forms (110). The three smaller lakes show a great falling off in 
numbers, Albert Nyanza mustering only 67 species of which 9 are endemic 
and Edward Nyanza 54 with 11 endemic species. Kivu, finally, only 
contains 23 types in all, 4 of which are peculiar to the lake. Thus, as 
regards its fauna, Tanganyika is distinguished from the other lakes not 
only by containing a larger number of forms, but especially by displaying 
a remarkable proportion of endemic species.’’! 
~The only African lakes that will be considered in the present discus- 
sion are Lakes Albert and Edward, belonging to the drainage of the Nile; 
and Lakes Kivu, Tanganyika, Moero, and Bangweolo, which flow into the 
Congo. These six important inland seas form a chain from north to 
south, along the eastern border of the Belgian Congo, between 28° and 
32° E. - Lakes Albert, Edward, Kivu, and Tanganyika occupy the 
deepest depressions of the Albertine Rift, a great, trough-like valley 
whose structure and biogeographic importance we have discussed before 
(see p. 505). Lake Moero appears to be situated in a similar, but much 
smaller trough, which, however, is entirely disconnected from the Alber- 
tine Rift in the north. Lake Bangweolo is of a different nature, filling 
merely a shallow depression near the Congo-Zambezi watershed. 
The numerical strength of the malacological faunz of these several 
lakes is given below in tabular form.” 
Number of Species, 
Subspecies, Number of Genera 
and Varieties 
Total Endemic Total | Endemic 
Pa cOwAl bert acute Serr, 17 8 Ral) 
Lake Bdward. 200. oo oe 19 10 9 a 
Lake Victorias: 4ie8", i 69 38 19 i) 
Take Tivo ae e aD Be 2 oi 
Lake Tanganyika......... 155 143 44 . 25 
Piece UMNGERO Seat wucaie ma 20 10 14 1 
Lake Nyaeas. cc. 70 ‘avr 13 
_.?Cunnington, W. A. 1920. “The fauna of the African lakes: a study in comparative limnology 
with special reference to Tanganyika.’ Proc. Zool. Soc. London, pp. 507-622. This paper contains an 
extensive bibliography. Cunnington’s figures are generally too low, as we shall have occasion to point out 
for the mollusks. 
1Figures for Lakes Victoria and Nyasa, compiled afresh for the purpose, are included for 
comparison. Our figures are quite different from those given by Cunnington which are generally too 
low, the author not having included many of Bourguignat’s species for Lakes Tanganyika and Nyasa. 
However, the species of this author were often based upon variations regarded as merely individual 
by other naturalists. For Lake Victoria the endemic genus Pseudocorbicula was overlooked by 
Cunnington. It should also be noted that our figures relate to the lakes themselves and do not include 
species that have only been found in their tributaries. 
