68 FEEDING WITH CYSTICEECUS CELLULOSYE. 



went far enough to prove that the Cysticercus cellulosce may also, in 

 the intestine of the dog, hecome developed into a Tcenia. 



The few Tcenice which were obtained from these Cysticerci 

 were, moreover, a source of great perplexity to me, for when I 

 attempted to define the species to which they belonged, I was 

 doubtful whether to consider them as appertaining to the Tcenia 

 serrata or to the Tcenia solium. The head and perfectly developed 

 joints accorded with either species, only the neck was longer and 

 more slender than that of Tcenia serrata, so that I was inclined 

 to regard them as Tcenia solium. Owing to the resemblance of 

 these tape-worms, Tcenia serrata and solium, to one another, I 

 was induced to submit the specimens of Tcenia solium in my 

 collection to a more searching examination, and to compare them 

 with the examples of the Tcenia serrata taken out of the dogs. 

 To my no small astonishment I found individuals amongst Tcenice 

 which had been taken from the human subject that were not to be 

 distinguished from Tcenia serrata. They had the short broad 

 joints with transversely wrinkled integument and undulating 

 posterior edge, just like Tcenia serrata ; the head, too, was formed 

 exactly like that of the latter, though the neck was more elon- 

 gated. Besides these, there were a few feeble individuals 

 amongst them, which fully corresponded with some of the tape- 

 worms produced from Cysticercus pisiformis ; and the eggs of the 

 Tcenia solium were not distinguishable from those of the Tcenia 

 serrata, so that I was forced to conclude that Tcenia solium and 

 Tcenia serrata were identical. In order to obtain a still clearer 

 insight into the matter, I further compared the heads with their 

 apparatus of hooks of Cysticercus pisiformis, longicollis, and 

 cellulosce with one another, and in these also I could find no 

 difference. 



With regard to the length of the neck, and the circumference 

 and contour of the joints, though there are, as I have already 

 partly shown, discoverable differences, they are not sufficiently 

 marked to rank as distinctive characters of two species of tape- 

 worms, and I must therefore maintain that Tcenia solium and 

 Tcenia serrata belong to one and the same species ; that they are 

 the extreme forms of a single species, connected by a series of 

 transitional forms. 



