838 UK. F. E. bEUJUAllI) ON A 



bundles of longitudinal muscular fibres which are to be noted in 

 the large worm. I believe also that the continuous large tube in 

 the immature Avorm is I'epresented by the cavities contained in 

 many of the segments of the adult worm, though the minute 

 structure, it must be confessed, differs in the two cases. Further- 

 more, the series of cavities in the adult worm lie very nearly in 

 the middle of the body, indeed quite in the middle of the body in 

 some segments; the tube in the young worm is, on the other hand, 

 as distinctly to one and the same side. But it must be borne in 

 mind that the position does vary in the young worm, and a further 

 flattening of its body might easily cause a greater similarity in 

 the position of the tube to that observable in the more fully 

 mature woi^m. 



§ Comparison with other Forms and Systematic 

 Position of the Parasite. 



Apart fi'om the question of proliferation by budding, to which 

 we shall return later, this Tapeworm presents a certain numbei- 

 of undoubted resemblances to Ct/sticercas fasciolaris (of rats and 

 mice, etc.), which becomes Tainia crassicollis in the Oat. Both 

 these foi'ms agree (I have compared the species which forms the 

 subject of the present paper with examples of the Gysticercus from 

 the common i'a,t) in possessing a long segmented body and a small 

 bladder postei'iorly. But in Gysticercus fasciolaris the bladder is 

 smaller and the body shorter than in my species, while the hooked 

 and suckered anterior end renders any confusion or detailed 

 comparison impossible. Nevertheless, the two forms have in 

 common the small bladder and long strobila. But while the one 

 occvipies the position in the body of its host of a sexual worm, i. e. 

 in a diverticulum of the alimentary tract, the other is found, as 

 are Cysticerci, encysted, and in the liver of its intermediate host. 

 Nor is it by any means certain that the species from the Mus- 

 quash is a member of the Tienioidea (Oyclophyllidea) at all. It 

 may well be a member of one of the lower groups of Oestodes, 

 We shall consider the arguments for and against the placing of 

 the worm among the Ttenioidea. 



It must be admitted at once that there are no absolutely con- 

 clusive arguments which point definitely one way or the other. 

 This, of course, may be explained on the assumption that we ai-e 

 dealing here with quite a new type of Cestode. In the meantime, 

 the structure of the woiin so far as it can be read does not favoui- 

 such an assumption, though it does not, for the matter of that, 

 appear to be necessai-ily contradictory of this possible view. As to 

 the other alternatives, the absence of a marked scolex with suckeis 

 is greatly against the reference of the worm to the Tsenias, but 

 the character of the terminal bladder, on the other hand, is on the 

 whole in favoui- of such a placing. This latter fact is obviously 

 against the supposition that the worm is a Plerocercoid of any 

 kind ; but the lack of a definite '* head " is as clearly in favour of 



