365 



Dr. Le Roux writes us that at the Farm Breezy Brae^ B. 

 tropicus is the intermediate host of Cotylophoron cotylophorum 

 of sheep and cattle. 



Bulinus cernicus Morelet. 

 Bulinus forskalii cernicus Clench 1930, Nautilus 43, p. 93. 



After a new study of a series of cotypes of Morelet's Physa 

 cernica, we have reached the conclusion that this form is fully 

 entitled to specific rank. In general outline it is intermediate 

 between B. crystallinus and B. canescens, forming one more link 

 in the passage from Bulinus, proper, to the subgenus Pyrgophysa. 



Bulinus (Pyrgophysa) canescens (Morelet). 

 Plate 18, figure 14. 



The Mus. Comp. Zool. has 7 cotypes of this species re- 

 ceived from Morelet, and obtained in Angola. It is a well- 

 characterized form, much less turreted than the subgenotype. 



Fig. n 



Bulinus (Pyrgophysa) forskalii (Ehrenberg). 

 Plate 18, figures 15-16. 



The Mus. Comp. Zool. possesses a series of 11 cotypes of Physa 

 semiplicata Morelet, from Angola, received from Morelet. One 

 of these specimens is shown in Plate 18, figure 15. After care- 

 fully comparing them with a series of B. forskalii from Egypt, 

 one of which is shown in Plate 18, figure 16, we are unable to 

 separate semiplicata even as a variety. We have also reached 

 the conclusion that Physa scalaris Dunker ( = P. dunkeri Ger- 

 main) is identical with B. forskalii. At any rate Dunker's figures 

 agree well with some of Morelet's cotypes of P. semiplicata. 



On the other hand, we cannot follow E. von Martens in regard- 

 ing Isidora lamellosa Roth as the young of B. forskalii. Small 

 specimens in our Egyptian lot of forskalii, some of them even 

 smaller than Roth's type, are much more slender and are not 

 visibly ribbed. Roth's figures are more like specimens from Lake 



Length 



Width 



A p. Length 



Ap. Width 



11.0 



5.5 



5.5 



2.5 mm. 



10.0 



4.5 



5.0 



2.5 



10.5 



5.0 



5.0' 



2.5 



10.0 



4.0 



4.5 



2.0 



