562 DR. F. E. BEDDARD ON 



the worm is large and has an obvious and thick muscular coat. 

 A peculiarity about this organ is that it does not lie in a straight 

 line extending inwards from the point of opening on to the 

 exterior, and thus at right angles to the long diameter of the 

 proglottid, as is so usually the case. The sac, on the other hand, 

 often bends at right angles near to its external pore and passes 

 backwards ; at other times it is more irregular in its folding. 

 Its large size is responsible for this folding, as the two cirrus-sacs 

 of a given segment would meet in the middle line did they run 

 straight inwards from the external pore. The cirrus itself is a 

 very fine tube upon the end of which I could detect no spines ; 

 it is coiled within the cirrvis. The sperm-duct after emerging 

 from the cirrus-sac forms a coil which is anterior to the sac and 

 near to the front of the segment. 



The vagina of this Cestode together with adjacent parts of the 

 genital system is shown in text-fig. 92. The most remarkable 

 fact is that that tube opens anteriorly to the cirrus, a position 

 which is made plain in the text-figure referred to. It would 

 also appear from a study of a series of sagittal sections — which 

 are the best in which to study these particular relationships — 

 that the vagina has not a separate orifice on to the exterior of 

 the body. But the truth of this conclusion will be doubted after 

 an inspection of text-fig. 92. For in that figure the vagina 

 seems to open separately, and of course anteriorly to the cirrus- 

 sa,c. It may be that this is at times the case ; but it is also 

 clear that in tracing the vagina in a series of sagittal sections the 

 tube is lost sight of in the walls of the male duct before the latter 

 reaches the exterior. I believe that among the Tetracotylea the 

 genus Tetrahothrium is the only genus in which the female 

 openings are in front of the male. It is true that in the Iciithyo- 

 tfeniidae generally, if not universally, there is an irregular alter- 

 nation in these conditions, the female duct lying in one segment 

 in front of and in another behind the male pore. But it is 

 doubtful whether this family is to be safely referred to the 

 Tteniadae. The figure referred to (text-fig. 92 C) shows the narrow 

 vagina lying in front of and parallel with the stouter cirrus-sac, 

 the two forming in this region a perfectly straight line, so that 

 their relative positions is a matter of ease to ascertain. I found 

 the same relations in other series of sections besides that from 

 which the text-figure referred to has been taken. Thus I am 

 able to state that there is not an alternation in the positions of 

 the male and female openings, as in Ichthyotainia. The vagina 

 is darkly stained and of small calibre in this tapeworm, the small 

 bore of the tube bearing a relation to the fineness of the cirrus. 

 Another remarkable circumstance is the nature of the recep- 

 taculum seminis and less mature and more mature proglottids. 

 In text-figure 92 C the slender vagina is seen to oj)en into a minute 

 spherical chamber or dilatation and to issue from the opposite side 

 as an equally slender tube. This chamber is, as I suppose, to be 

 compared to a receptaculum seminis ; but it has in this section 



