THE ANIMAL PARASITES OF MAN 



from each testis, unites with those that are contiguous, and 

 finally discharges into the muscular vas deferens that is situated 

 in about the middle of the segment. According to its position the 

 genital pore opens on a lateral border or in the middle line 

 towards the front ; it is much convoluted or twisted and fre- 

 quently possesses a protuberance termed the vesicula seminalis. It 

 finally enters the cirrus pouch, which is usually extended ; within 

 the cirrus pouch lies the projectile end, the penis, which is sometimes 

 provided with booklets . 



The male sexual orifice almost always lies by the opening 6f 

 the vagina in a genital atrium, the raised border of which rises 

 above the edge of the segment and forms the genital. pore (fig. 125). 



A. 





FIG. 126. Central field of the proglottis of Dibothriocephalus latus. A., 

 from the ventral surface ; B., from the side. Cp., cirrus pouch ; Vs., vitellogene 

 gland ; Ov., ovarium ; Sg., shell gland ; T., testicles ; Ut., uterus ; Va., vagina ; 

 Vd., vas deferens. (From Claus.) 



The vagina, like the vas deferens, usually proceeds inwardly 

 or posteriorly, where it assumes a spindle-shaped form (recep- 

 taculum seminis) ; its continuation, the spermatic duct, unites 

 with the oviduct, the common excretory duct of the ovaries. 

 The ovaries, usually two in number, are represented by com- 

 bined tubular glands in the posterior half of the proglottis, and 

 they spread out into the medullary layer, but are also distributed 

 spread out ventrally on the transverse plane. 



At the origin of the oviduct there is frequently a part which 

 is dilated and provided with annular muscles, and which 



