14 DR. F. E. BEDBARD ON 



There are various points in the structure of the reproductive 

 system of organs which help to fix the distinctness of this species 

 from others, and especially from Iclitliyotmnia hiroi, to which it is 

 most nearly akin. The testes occupy the greater part of each 

 ripe proglottid, and there is no very definite median area free 

 from them. There is nothing so definite, for instance, as the 

 "conditions figured by Schwarz in Ichthyotcenia uattereri*. In 

 horizontal sections of a series of mature segments the difficulty 

 of distinguishing the boundary lines between successive segments, 

 plainly felt on examination of the entire worm with a lens, is 

 increased by the lack of a definite break between the reproductive 

 systems of each segment. There is an appearance of complete 

 continuity not seen in corresponding sections of the other species 

 which I have studied. 



The vas deferens behind the cirrus-sac is closely coiled, this 

 coiled region reaching quite or nearly halfway across the pro- 

 glottid. The calibre of this region of the vas deferens does not 

 vary in any appreciable way from point to point. That is to say, 

 there is not, so far as I have been able to ascertain, any vesicula 

 seminalis like that of Ichthyotcenia gracilis described in the 

 present paper. It is important to note this fact, since in /. hiy-oi 

 the existence of a vesicula behind the cirrus-sac has been stated, 

 but Schwarz was not able to see it. The tangled coil of the vas 

 deferens lies across the segment with a slight inclination towards 

 the anterior margin. Within the cirrus-sac the vas deferens is 

 also coiled. 



The present species is the only one of those known to me at 

 first hand, and which are described in the present paper, which 

 possesses an armed cirrus. This organ, when protruded, is covered 

 extei-nally with very numerous and closely-set hooks. In sections 

 through the cirrus-sac, where it is not protruded, the spines can 

 be seen lining the canal of the cirrus. Schwarz figures in the 

 case of Ichthyotoinia marenzelleri t an actual protrusion of the 

 cirrus-sac itself in an apparently unaltered condition. There is 

 no doubt that in the species with which I am here concerned 

 the outpushing of the cirrus is an eversion of the cavity of the 

 cirrus, since the spines lining the latter become external in the 

 everted organ. 



The cirrus-sac and vagina open ver}^ slightly in front of the 

 middle of the lateral margin of the segment. The generative 

 apertures, of course, alternate from the side of the body in 

 different segments, and there is also, as in many but not in all 

 species of the genus, an alternation in the relative positions of 

 the two orifices, the cirrus being sometimes anterior and some- 

 times posterior. The generative ducts pass between the dorsal 

 and ventral water-vascular tubes, and there is in the present 

 species no cloaca genitalis. This is rendered particularly evident 

 in one specimen which I mounted entire in glycerine, and of 



* Loc. cit. Taf. i. fig. 2, A. 

 t Zioc. cit. Taf. iv. fig. 12, c, b. 



