397 



On Experimental Infection of Ducks with Cysticercus 

 Coronula Marazek (Rosseter), Cysticercus Gracilis (Von 

 Linstow), Cysticercus Tenuirostris (Von Hamann). 



By T. B. Rosseter, F.R.M.S. 



(Bead March 19th, 1897.) 



Plate XVIII. 



My intention this evening is to lay before you a few facts 

 in connection with the experimental infection of ducks (Anas 

 boschas dom.) with the Cysticercus, or intermediate stage of 

 Dicranoiamia coronula, Drepanidotainia gracilis, and Drepanido- 

 tcenia tenuirostris. Each of these three tapeworms I have found 

 parasitic in the intestine of the domestic duck, they having 

 become infected, no doubt, from their feeding on the crustaceans 

 which nursed these cystic bodies and which existed in the pond 

 which the ducks daily frequented, and from which my specimens, 

 both of the Cysticercoids and the specific nurse, were taken ; and 

 with which I artificially infested, experimentally, my ducks so as 

 to reproduce the adult tapeworm. 



My reason for doing so is because of certain statements made 

 by Dr. Stiles in his recent work on the " Tapeworms of Poultry,'' 

 Washington, 1896, Bulletin No. 12, issued under the direction of 

 Dr. Salmon, Chief of the Bureau of Animal Industry, U.S. De- 

 partment of Agriculture. This is a work which must commend 

 itself to helminthologists, especially those who are working 

 exclusively on Avian helminths. In this work he casts a doubt 

 on the accuracy of these cysticercoids, mentioned above, as being 

 the larval form of these specific tapeworms, owing to the want of 

 production of the final stage, or Taenia, from the direct infesta- 

 tion of the duck with the cysticercus. In this publication Dr. 

 Stiles has collected the scattered works of those European helmin- 

 thologists who, during the present century, have investigated, and 

 published their researches, in connection with Avian Taenia ; and 

 a speciality is made of the known life-history, or otherwise, of 

 those tapeworms which are particularly applicable to poultry. 

 Hitherto it has been usual to classify, indiscriminately, all tape- 



Journ. Q. M. C, Series II., No. 41. 28 



