184 Transactions of the Royal Society of South Africa. 
with Paramphistomids about three months after they had grazed on the 
infected grass. It needed no jjarticular ingenuity to regard the common 
Isidora tropica as the intermediate host of the locally known Param- 
phistomid. After a careful examination of the rediae and cerceriae in the 
Fig. 5. 
intermediate host Isidora tropica, I carried out a feeding experiment. 
Three young sheep and a young lamb were used for the purpose. The sheep 
were obtained from a dry locality in the Karoo from a small flock I knew 
to be free of Paramphistomids ; the lamb I had reared myself, to make sure 
that it was free of infection from any source whatsoever. For three weeks, 
at the rate of two to three feeds per week, they were fed on grass heavily 
infected with encysted cerceriae. As a result of continued and careful 
