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Physopsis africana Krauss 
Plate IV, B 
Shell sinistral, higher than wide, globose, umbilicate, perforate or 
imperforate, whitish to chestnut brown, sculptured with fine growth lines; 
whorls evenly rounded. Aperture ovate-lunate; outer lip sharp; columella 
truncate. Adult shells (with 4-5 whorls) are 14-20 mm. high. 
Distribution: Natal, Transvaal, Southern and Northern Rhodesia, 
Mozambique, southern Tanganyika. 
This species, Bulinus truncatus, and Biomphalaria boissyi are the chief 
vectors of the human schistosomes in Africa, 
Bulinus truncatus (Audouin) 
Plate IVA 
Shell very similar to Physopsis africana, but with a straight or slightly 
curved rather than truncate columella, and shouldered whorls. Adults 
(with 4-5 whorls) are 14-20 mm. long. 
Distribution; Northern and eastern Mediterranean countries, Egypt, the 
Sudan and Uganda, 

