lARVAL TP.EMATODES FROM FRESH-WATER SNAILS 115 



the old nest, but kept oiiL three of iiverage size for the 

 jmrpose of iiiea.siirei)iei>t. The eggs are like a round hen's 

 egg, the long axis measuring half an inch. They are en- 

 cased in a tough white skin Avhich has a tendency to 

 harden when exposed to the air. The eggs varied slightly 

 in size hut the difference is small. 



What struck me most Avas: (a) that a chameleon, so 

 ill-adapted for the purposes, should be able to dig such 

 a deep hole in very stiff clayey soil; (b) the number of 

 eggs laid; on seeing their size and number it seemed 

 almost incredible that they could have been laid by one 

 chameleon, unless these eggs swell considerably after 

 being laid; (c) how the young chameleons can work 

 their Avay to the surface through from six to eight inches 

 of clav. 



Larval Trematodes from some Fresh-water Snails. 

 By F. (j. (^vwsTON, M.D. (Cantab). 



Whilst examining the fresh-Avater snails of Natal and 

 the Transvaal, 1 have encountered the larval stage (7? 

 several dilTerent species of trematode Avorm. Some of 

 these develop in freely movable rediae, Avhilst others de- 

 Telop in sp»)rocysts Avithout the formation of redi;ie. 



At one time I thought that members of the Schistosome 

 group AAcre confined to Physopsis but this view has to be 

 modified in Adew of the isolation of typical Schistosomes 

 from Isidora schakol. These Schistosomes are quite dis- 

 tinct from the Bilhai-zia Avhich I haA^e found deA^eloping 

 only in Physopsis africaua and Mr. Hewitt of the Albany 

 Museum at GrahamstOAvn suggested that they might be 

 a ])arasite of the Avater-rat. They are not altogether 

 unlike a cercaria which infests Physopsis at Pieter- 

 maritzburg Avhich, according to Dr. E. Warren, has the 

 appearance of an avian trematode. 



