305 



Cysticercus Venusta (Rosseter). 

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



(Read November 20th, 1896). 



I took this Cysticercus from Langham House Pond in 

 G-orstly Wood, near Bishopsbourne, five miles from Canter- 

 bury, the same pond from which I took Cysticercus liophallus, 

 and, as in the former case, it was making Cypris cinerea its 

 " nurse." It was parasitic in about 6 per mille of the Cypris, 

 and was commensal with Cysticercus gracilis and C. coronula. 



This number, small as it may seem, warranted me in trying 

 to produce the mature tape-worm by feeding, or rather inject- 

 ing, ducks for that purpose. Accordingly in the latter part of 

 May I purchased some ducks, and one of these I isolated and 

 fed every other day for twenty- one days. At the end of the 

 twenty-one days I killed the duck, and carefully examined 

 with the aid of a 2in. and a ^in. objective the contents of 

 the gizzard and intestine by washing and precipitating the 

 undigested food and excreta. The duodenum, more especially, 

 was carefully searched, knowing from past experience that 

 they, the tape-worms, bury their scolices in the soft mucous 

 membrane ; but, although I found specimens of Tcenia tenui- 

 rostris, T. gracilis, and an abundance of T. coronula, yet I failed 

 to find a single specimen of the perfect Taenia of this Cysti- 

 cercus. 



In the first week of August I again isolated another duck, or 

 rather a young this-year's drake, and commenced feeding it 

 with strainings from this particular pond ; but on the twenty- 

 second of the same month I bargained with the man at the 

 lodge to sell me the two remaining ducks be had on the pond. 

 One of these was killed immediately on arrival home, and the 

 alimentary tract thoroughly and carefully examined in a similar 

 manner to that described above, but beyond a few specimens of 

 T. tenuirostHs and T. gracilis — six in all — the experiment was 

 helminthologically a total failure. This was remarkable, as 

 these two ducks had been on the pond over two years, and the 



Journ. Q. M. C, Series II., Xo. 40. 22 



