72 Bulletin American Museum of Natural History [Vol. LIII 
PAGE 
A. West African Subregion... Meneses ey. 488 
1. Lower Guinea Forest Discus, wie ey 288 
2. Ubangi Savanna Wiehe, oe. Renee teeth ys, AO4 
3. Southern Congo Savanna District................ 496 
4. Uganda-Unyoro Savanna District................. 500 
B. East African Subregion......... Ree ees O04 
5. Eastern Mion tan Distuct., ieee sh. » 004 
6. East African Highland Piiriet. eee ly: ss. OLD 
7. Rhodesian Highland 5 oe ee Petes OLB 
Ecology and Distribution of the Fresh-water Mollusks................. 519 
Tie Hcologieah Waetorescuy wk ye ead Cale och hi elbatwnard totais wana Bie 6s 520 
Mollisk: Paana: of Stammant Water tc2 20 oc eies pte oa ee es 540 
Mollie fauncsor Miowine Water. <) eos eee eee ee cease. 545 
Coastal Rivers of the Belgian Conge..0n.;. 60. ceesnd se. «ss 549 
Congo River Overeiii se ees ok MONS sae. 5 550 
Nile River Systeme 0. a ays rn. edie tet ee a 570 
Mollusk Fauna of the Central African Lakes AO ORME Ay ey Uep a 573 
Lake Albert.......... a er ete ere Ce ease lb Sw es 575 
eae: Thy Bie eae ie eee tA RRC sewed vs. OFO 
Ce gk ce ee care Sr aetiaige) Wins gest eed y aigce esi « « 579 
ake “Pantenyiicny ka cerraeie Wcae cian acres ee eee. eas OSL 
Tepe VEOCR Os. setae et me teh hae ate ne ra ee AMM, Tee lontow os as 595 
Lake Bangweolo........ Pee a .:.- $98 
Notes on the Relations of the Edhiopiaa bo re Beene: Bees 698 
Recent Additions.to the Land Mollusks of the Belgian Canna... elas GOL 
INTRODUCTION 
The present report, like its predecessor treating of the land mollusks 
of the Belgian Congo, is based primarily upon the collections of Herbert 
Lang and James P. Chapin of the American Museum Congo Expedition. 
1909-1915. This material is extensive, comprising over 15,000 
specimens and representing 68 species, subspecies, and mutations. 
Several of these forms are present in large series, of great interest for a 
study of variation. These collections were supplemented by material’ 
taken by the junior author in 1913-1915, as well as by specimens from 
the Congo Museum at Tervueren, Belgium, and from the Academy of 
Natural Sciences of Philadelphia. Altogether, 183 species and subspecies 
were studied, of which about 180 are either represented in the present 
collection, or will be added to it through the courtesy of the above-named 
institutions. The total number of aquatic mollusks at present known 
from the Belgian Congo is 328, which includes the fauna of the Great 
Lakes and also some rather dubious records. Credit has been given to 
each collector under the respective species. 
