838 DR. F. E. BEDDARD 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 worm is represented by the cavities contained in 

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

 structure, it must be confessed, dilfers 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 moi'e fully 

 mature worm. 



§ Comparison with other Forms and Systematic 

 Position of the Parasite. 



Apart from the question of proliferation by budding, to which 

 we shall return later, this Tapeworm presents a certain number 

 of undoubted resemblances to Cysticercus fasciolaris (of rats and 

 mice, etc.), which becomes Taenia crassicoUis in the Oat. Both 

 these forms agree (I have compared the species which forms the 

 subject of the present paper with examples of the Cysticercus from 

 the common rat) in possessing a long segmented body and a small 

 bladder posteriorly. But in Cysticercus 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 

 occupies 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 Tsenioidea (Cyclophyllidea) 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 Taenioidea. 



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 are 

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

 the structure of the worm so far as it can be read does not favour 

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

 appear to be necessarily contradictory of this possible view. As to 

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

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

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

 whole in favour 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 



