LIFE-HISTORIES OF TREMATODES. 161 



when mature, vary from 5mm. to 12mm. long by 4mm. to 5mm. 

 broad, identical with those common in cattle in Johannesburg 

 Abattoir. Many full-grown adults are about 10mm. long and 4mm. 

 broad. The anterior sucker is large; the oesophagus forks, 

 the two branches of the gut passing backwards almost to the large 

 acetabulum or caudal sucker. The two testes are slightly lobulate, 

 one at a slightly lower level and posterior to the other. They are 

 laterally placed and their fields do not overlap. There is a great 

 development of the pars muscularis of the cirrus. The small ovary 

 is posterior to the testes, near the anterior border of the aceta- 

 bulum. The vitellaria extend forwards almost to the anterior 

 sucker. Numerous ova are produced, which are rather slow in 

 maturing, at any rate under laboratory conditions. If the 

 miracidia reach Isidora tropica they enter the snail and the life- 

 cycle of the fluke recommences. 



The life-cycles of two other larval Amphistomes are under 

 investigation. 



As far as can be ascertained from the literature available this 

 Paramphistome would seem to be Paramphistomum calicophorum 

 of Fischoeder, now placed by Stiles and Goldberger (1910) pro- 

 visionally in their subgenus Cauliorchis. Further work is in pro- 

 gress, and I believe that Mr. C. S. Grobbelaar, of the University 

 of Stellenbosch, is also working on this or an allied species of 

 Amphistome, so that further information is likely to be available. 

 The eyespotted cercaria that I have used I cannot identify with 

 certainty as the Cercaria frondosa of Cawston, as that author gave 

 no critical details, while it does not agree in certain respects with 

 C . frondosa described by Faust from preserved specimens sent him 

 by Cawston. However, some of the more obvious structural fea- 

 tures of the cercaria have already been mentioned by me in the pre- 

 ceding. 



Preventive Measures. 



Preventive measures against infection of vertebrates by the 

 different species of Fasciola and by Paramphistomum may be sum- 

 marised. As infection is by way of the mouth in both cases, access 

 to herbage immediately bordering water must be prevented by 

 fencing, and an adequate supply of water that has stood for two 

 days must be provided for cattle and sheep. Any encysted cercariae 

 will be found on the sides of the vessel in which the water has been 

 contained prior to use. Snail infestation of water should also be 

 prevented by the use of domesticated ducks, as mentioned pre- 

 viously in connection with Schistosome infections. 



ECHIXOSTOMES. 



(1) Echinostomum fulicae, n. sp. 



The adult Echinostome, for which I suggest the name 

 Echinostomum fulicae, was found in the alimentary tract of the 

 redknobbed coot, Fulica cristata. The larval stages are passed in 

 either of the snails, Tomisia ventricosa or Isidora tropica, as I have 

 determined experimentally. 



