T. B. ROSSETER ON CTSTICERCUS OF T2ENIA LIOPHALLUS. 315 



taken from the mucous membrane of the intestine and is 

 occupying our attention. This observation is more applicable 

 to the hooks with which the scolex is furnished. There are 

 cases in which the scolex is inerme, although amongst those 

 Cestodes, or rather tape-worms, who make the class "Avis" 

 their host the inerme scolex is rare, and we have not those 

 familiar landmarks, the hooks, to guide us. In such a case we 

 fall back on the contour and formation of the suckers, the 

 rostellurn, if it exists, or the histology of the scolex itself. 

 But when the scolex is furnished with hooks we are then 

 enabled to deduce or formulate our ideas, and can build up, so 

 to speak, one of these lowly organisms, and accurately, by the 

 aid of the hooks, define its species. 



This observation is more especially applicable to the 

 Cysticercoid stage of these tape- worms, for here the hooks 

 are the chief factors in forming our decision. 



Krabbe, who has given us a beautiful monograph of the 

 known Taeniae of birds, has also given us what may be called 

 a "Book of Reference" in his drawings of the different parts 

 of each known species of tape-worm, more especially with 

 respect to the hooks of the scolex. Although beyond the 

 dimensions given by him of the hooks, I am unacquainted with 

 the text of his work — being unacquainted with Danish — yet so 

 beautifully are they, the hooks, drawn, and so accurately are 

 they portrayed, that they literally speak for themselves, and 

 the helminthologist needs no textual description to define his 

 specimen of tape-worm or allocate the species of Cestode to 

 which his Cysticercus is affiliated. And thus it is I am 

 enabled to define and place in its true position Fig. 13 as being 

 the Cysticercus, or intermediate stage, of Taenia liophallus. 



The Cysticercus of this Taenia I found making Cypris cinerea 

 its intermediate host or nurse. The Cypris was taken from a 

 pond in Gorstly Wood, one and a half miles from the village of 

 Bishopsbourne on the Elhatn Valley Railway, about five miles 

 S.E. from Canterbury. It is a very old pond, and the man 

 who resides in the cottage close to the pond has kept ducks on 

 it for years past, so one naturally infers that the duck as well 

 as the swan must be its — Tcenia liophallus — final host. 



There is a great similarity between the hooks of the scolices 

 of T. liophallus (Figs. 14 and 15) and those of T. setigera (Figs. 



