364 



Length 



Width 



Ap. Length 



Ap. Width 



7.0 



4.5 



4.5 



2.0 mm. 



7.0 



4.0 



4.5 



2.0 



7.5 



4.5 



4.5 



2.5 



7.5 



4.5 



4.5 



2.5 



7.0 



4.5 



4.5 



2.0 



5.2 



3.4 



3.3 



1.5 



Fig. 13 



Bulinus tropicus (Krauss). 

 Plate 18, figure 12. 



B. tropicus is probably the most common and most widely dis- 

 tributed of the South African species of the genus and consequent- 

 ly has prime importance as a potential host of helminth parasites. 

 We have seen in all five lots which appear to be tropicus, although 

 there is some variation in the development of the spire. One lot 

 was obtained by Dr. F. G. Cawston in Congeela Park, Durban, 

 Natal. The other lots were sent by Dr. P. L. Le Roux, from the 

 following localities: Pretoria, Transvaal, close to the town; 

 Breezy Brae, Arhngton Sta., Orange Free State; Fickburg, 

 Orange Free State; and Kei Road, Cape Province. 



Dr. Le Roux has figured this species (1929, 15th Ann. Rept. 

 Dir. Vet. Serv. Union South Africa, p. 436, fig. 14 to 17 and 32 to 

 33). We do not believe that Bulinus schackoi (Jickeli), described 

 from Abyssinia, is identical with B. tropicus. Jickeli's figures are 

 much more hke the form from Uganda, which we show in our figure 

 11 a^B. masakaensis (Preston). 



Bulinus craveni (Sturany ) ( = Physa lirata Graven) is certainly 

 identical with tropicus, as claimed by Gonnolly (1912) and Dupuis 

 (1923). B. cTjrtonotus (Bourguignat) , however, is, we beheve, a 

 distinct species, as shown above. 



^ength 



Width 



Ap. Length 



Ap. Width 





10.5 



8.0 



7.5 



4.0 mm. 



Congeela Pari 



11.0 



7.0 



7.5 



4.0 



" 



11.5 



8.5 



6.5 



5.0 



Pretoria 



12.5 



8.0 



8.0 



4.5 



" 



10.0 



7.5 



7.0 



4.5 



Kei Road, Fig. 



9.5 



6.5 



6.0 



3.5 



" 



12.0 



8.5 



8.0 



4.5 



Fickburg 



13.0 



9.5 



8.5 



5.0 



" 



9.0 



7.5 



6.5 



4.0 



Arlington Sta 



9.5 



6.5 



6.5 



4.0 



" 



1^ 



