358 



Bulinus coulboisi (Bourguignat). 



A young shell collected by the senior author on the beach of 

 Lake Tanganyika, at Albertville, Belgian Congo, agrees well with 

 Bourguignat's description and figures of coulboisi. We also refer 

 to the same species a series of poorly preserved Bulinus found by 

 the senior author on the northeastern shore of Lake Kivu, at 

 Mai na Moto near Kisenje. None of our specimens are fit to be 

 figured or measured. 



B. randabeli (Bourguignat) is probably not separable from B. 

 coulboisi. Both may be identical with B. zanzebaricus (Clessin), 

 originally described from Zanzibar (perhaps really not from the 

 island, but from the mainland), but reported also from Ruanda, 

 east of Lake Kivu, by Thiele. 



Bulinus masakaensis (Preston). 

 ' Plate 18, figure 11. 



Preston's species seems to be represented by a small lot of 

 snails collected by the senior author at Bufundi, on the western 

 shore of Lake Bunyoni, Uganda. As may be seen by comparing 

 our figures, this snail is exceedingly similar to the South African 

 B_. corneus and perhaps will eventually be united with it. The 

 columella shows, however, a slight twist. 



Fie. 11 



Bulinus corneus (Morelet). 

 Plate 18, figure 7. 



A series of specimens from Swinburne, Orange Free State (Dr. 

 F. G." Cawston, collector), appear to be Morelet's species. E. 

 von Martens and Connolly have synonymized corneus with the 

 earlier B. zanzebaricus (Clessin), and this procedure may be cor- 

 rect. The species is, however, quite distinct from the specimens 

 of Lakes Tanganyika and Kivu which we call B. coulboisi. 



Length 



Width 



A p. Length 



A p. Width 



10.0 



6.5 



7.5 



3.5 mm. 



10.0 



6.5 



6.5 



3.5 



Length 



Width 



Ap. Length 



Ap. Width 





11.5 



8.0 



7.5 



5.0 mm. 



Fig. 7 



• 10.5 



7.5 



7.5 



4.5 





10.0 



7.0 



7.0 



4.0 



Apex corroded 



8.5 . 



7.5 



6.5 



4.0 





