272 T. B. ROSSETER ON DREPANIJDO TAENIA UNDULATA (kRABBE). 



the vagina together with the cirrus, and is apparently clasped by 

 the vulva, for, on withdrawal, one frequently sees portions of the 

 endothelid of the vagina drawn away by the act of retrocession 

 of the spinous sheath, and there are times when the spinous 

 sheath itself is torn away and left in the vagina, thus exposing 

 the smooth cirrus. 



The cirrus-pouch (Fig. 4, b) runs two-thirds of the whole 

 length of the segment anteriorly, but posteriorly to the vaginal 

 canal. The vas-deferens within the pouch is serpentine, and, 

 emerging from it, forms a series of loops and gradually descends 

 towards the dorso-median line of the segment, and then runs 

 proximally. In its course the vasa-efferentia make a junction 

 with it, and it thus receives the spermatozoa from the testes. 

 These tortuous, looped semeniferous tubules, together with the 

 serpentine vaginal canal, find their counterpart morphologically 

 in the higher orders of nature — the vasa-deferentia of the insecta 

 (Xepa) and the Mullerian duct of the salamander being cases 

 in point. 



The female genital pore (Fig. 5, e) is as insignificant exteriorly 

 as that of the male. It is situated on the extreme anterior 

 lateral-ventral corner of the segment, and is over-lapped and 

 hidden from view by the posterior proximal border of the 

 preceding segment, so much so that the cirrus, for the pur- 

 pose of copulation, has to force its way through the angular 

 terminal aperture of the preceding segment. It requires delicate 

 manipulation with fine dissecting needles to lift up the posterior 

 portion of the preceding segment in order to trace the pore and 

 course of the vaginal canal. The female pore is a simple aperture 

 in the tissue, devoid of papillae or protuberance. In stained 

 st ctions the whole length of the vagina is seen to be composed of 

 circular and longitudinal muscular fibres. As the vaginal canal 

 (Fig. 5,/) recedes it becomes narrower, forms a series of loops, 

 mid then distends itself into a curved sac — the receptaculum 

 seminalis, (Fig. 5, y) — whose distal end descends in the segment, 

 and from which emerges the efferentia, or fructifying canal. 



