86 ' Bulletin American Museum of Natural History [Vol. LIII 
Spekia zonata (Woodward), and Edgaria nassa (Woodward). Between 
1850 and 1880 a few species were obtained in some of the affluents of the 
Congo by Schweinfurth, Capello and Ivens, and Wissmann. Since then 
additions to the fresh-water mollusk fauna of the Congo have been made 
by a small number of collectors who were mentioned in the introduc- 
tion to the report on land mollusks. On the whole, however, the aquatic 
species appear to have been somewhat neglected, with the exception of 
those of the Great Lakes where a great number of travellers and mission- 
aries have gathered quantities of shells and where several expeditions 
have formally investigated the fauna. 
SUGGESTIONS TO COLLECTORS 
Challenging the available data, we find that our present knowledge ~ 
of the fresh-water mollusks of the Belgian Congo is even less complete 
than that of the terrestrial species. The main river, Congo-Lualaba, 
has only been somewhat satisfactorily investigated at its estuary 
(between Boma and Banana), at Stanley Pool, near the Stanley Falls, 
and between that locality and Kasongo. Of its many tributaries none 
can be said to have been more than superficially touched; thus, we have 
a few records from the Ubangi, Uele, Dungu, Ituri-Aruwimi, Tshopo, 
Luvua, Luapula, and some of their smaller affluents. Not more than a 
dozen species are listed for the extensive drainage of the Kasai. Although 
much attention has been paid to the fauna of the Great Lakes, additional 
discoveries will undoubtedly still be made there. Lakes Bangweolo, 
Kivu, and Albert especially need to be more fully investigated. Nothing 
is known as yet of the molluscan fauna of the Semliki. 
The possibilities for making malacological discoveries in the waters 
of the Belgian Congo are therefore excellent in every respect. There are, 
it is true, but few places where water shells are at all abundant and 
conspicuous, yet a thorough search will reveal] a fair number of species 
in almost any locality. The neighborhood of Stanleyville, for instance, 
has yielded 31 forms of aquatic mollusks, although there is no apparent 
reason why that locality should be favored. 
Many species may often be picked up by hand from the rocks in the 
rapids, from floating pieces of wood, and from the muddy or sandy shores 
of rivers. Certain of the smaller snails, such as Ancylus, can be obtained - 
only by carefully examining the stalks of water plants, and especially 
the under side of floating leaves, also stones and shells. The bottom layer 
of ponds and pools or shallow streams can be scooped out or scraped up 
from the shore or from a canoe with a net made of a strong wire bent into 
