152 t. b. rosseter on hymenolepis upsilon, 



Description of Genitalia. 



The genital pores are unilateral on the proximal lateral bordery 

 both male and female being in the same sinus. The male pore 

 is anterior to the female. The male genital pore is circular, and 

 has a diameter of 0"013. mm. The bursa copulatrix lies diagonally 

 in the segment, and occupies about two-thirds of the angle of the 

 segment, and is 0*017 mm. in cross section. It contains the 

 vesicula seminalis interior, and the cirrus, with its pouch and 

 sheath. The cirrus is hispid ; when exerted it is 0'024 mm. 

 in length, 0"007 mm. in breadth, and is not claviform. The 

 sheath is a prolongation of the cuticle of the vesicula seminalis 

 interior. It is 0'02 mm. in length. From the distal end of the 

 cirrus and through the sheath runs a convoluted duct, which ^ 

 expands into a heart-shaped expulsion bladder, and from this 

 succeeds the vesicula seminalis interior, w^hich is a long narrow 

 sac occupying the middle portion of the bursa, and is filled with 

 sperm. At the end of the sac is a protrusible fundus with a 

 circular orifice and a sinuous duct. The w^all of the bursa 

 coalesces with this duct, and is prolonged into the ductus efferens 

 of the vesicula seminalis exterior, which is an orbicular sac with 

 a diameter of 0*074 mm. ; the sperm-mass occupies the central 

 portion of the clear space. The three semi-orbicular testes have > 

 each a diameter of 0*034 mm. ; their efferent ducts, which are 

 offshoots of the membranous sac, coalesce with the vas deferens, 

 which is an arched duct from the proximal to the distal testes, 

 and it then runs vertically to the vesicula seminalis exterior 

 (Fig. 8). 



The female genital pore is very obscure. It is a simple oval 

 aperture ; the vagina is campanulate and the vaginal canal 

 filiform. It terminates in the receptaculum seminis, which in 

 the mature hermaphroditic segment lies diagonally, but in the 

 succeeding segment is then nearly vertical and pyriform. Its 

 vertical axis is 0*07 mm. and its equatorial 004 mm. The; 

 yolk-gland is orbicular ; it is situated between the ovaries in 

 the posterior middle portion of the segment ; it is composed : 

 of a series of lobules, from whose converging ducts issues a 

 common duct, the ductus efferens. The shell -gland is com- 

 posed of three acini, a comparatively large central one and -: 

 two small, one on either side; their common duct, like the. 



