T. B. KOSSETER OX HYMENOLEPIS FARCIMIXALIS. 305 



The female genital pore is situated posterior to the male in 

 the same sinus (Fig. 11, v.). 



The vagina is ampulla-shaped with a smooth interior. The 

 vulva is composed of circular muscular bands radiating from 

 the proximal endoderm of the vagina, their apical ends forming 

 the vaginal pore. The pore has a diameter of 0*009 mm. In 

 mature segments and previous to coition this — like the male 

 pore — is elevated 0*014 mm. in the form of a truncated cone 

 which at the time of coition enters the orifice of the pouch. 

 For this reason I look upon the pouch as an exhaust cup for 

 fixation during copulation, because when the receptaculum 

 seminis is filled with sperm the vulvular muscles are relaxed, 

 the pouch and cirrus are released, and, in some instances of 

 which I have specimens in my preparations, the excess of 

 spermatic fluid -is seen issuing from the cirrus. The relaxation 

 of the radial muscles causes the vulva to resume its normal 

 position in the sinus. 



The vaginal canal (Fig. 3, v.c.) at the base of the vagina is 

 a sinuous filiform duct. In its further course it slightly dis- 

 tends, again becomes filiform, and terminates in the receptaculum 

 seminis (Fig. 3, r.s.). The receptaculum is a long attenuated 

 sac; its diameter at its most distended part, when it is filled 

 to repletion with spermatozoa, is but 0*078 mm. It is homo- 

 logous with the vesicula seminalis. This analogy is the more 

 striking as the two organs lie side by side in the same plane 

 in the segment. The efferent duct or fertilising canal is short, 

 the ovarian ducts forming a junction on either side in close 

 proximity to the pore of the ductus efterentia. 



The ovaries (Fig. 3, ov.) are racemose. Each raceme is filled 

 with ova, and throws off a duct into the main or ovarian duct 

 (Fig. 3). Their separation into proximal and distal ovaries is 

 only made perceptible by the junction of their ducts with the 

 fertilising duct. 



The yelk-gland (Fig. 3, y.y.) is situated in the median line 

 of the ovaries. It is somewhat reniform, 0*084 mm. long and 

 0*051 mm. in diameter. 



The shell-gland (Fig. 3, s.<j.) is pyriform, and lies proximal of, 



