Some South African Cercariae 203 



TABLE SHOWING RESULTS OF EXAMINATION OF 

 FRESH-WATER SNAILS FOR CERCARIAE. 



« 



ri CO 4-1 



2S as S Xl-ciS i^c ^-sn 



«g « -^ - Sg'S -ii: Si5 S 



*g "- "= "^ ''^o SSo S2m -S 



Limnaea natalensis 



1487 81 39 30 5 13 



PJiysopsis africana 



1073 311 2 152 7 



Isidora tropica 



600 12 2 2 4 1 



Planorhis pfeifferi 



345 10 18 4 5 



Isidora forsTcali Ehrul) 



289 9 2 2 



Tiara tuberculata (Miill) 



422 IS 1 3 3 



Ancylus including Ferrissia turnupi Walk, and Bumupia caffra 



414 (Ers.) and Ferrissia fontinalis Walker. 



Planorhis including Segmentina planodiscus and P?(mor6i5 

 273 costulatus Krauss and PlanorHs anderssoni Auc. 



Cerithidea decollata L. from Isipingo 



59 Assemania hifasciata Ner. from Isipingo. 



Littorina hifacciata Ner- from Isipingo 



92 

 Sept aria from Umbogintwini 



4 

 Isidora diaphana Krauss from Umgeni, 11 ; and Isidora natalensis, 

 (Krs-) junr. from the North Coast of Natal. 



REACTION OF BILHARZIA CERCARIAE TO LIME, SALT AND 

 ANTIMONIUM TARTRATE. 



Cercariae from Ph\)SOpsis added to Salt Solution (gr. 10 to 

 10 c.c. of water). Practically all cercariae dead and shrivelled 

 in five minutes. 



Cercariae from Ph^)sopsis added to Salt Solution (gr. 10 to 

 40 c.c. of water). Practically all dead within half an hour. 



Cercariae from Physopsis added to Solution of Lime (fresh) 

 (gr. 10 of fresh slaked lime in 20 c.c. of water). All cercariae 

 killed in five minutes. 



