404 T. B. ROSSETER ON THE ANATOMY OF 



with the vas deferens. They have individually a length of 

 0*145 mm. and a width of 0*057 mm. At no period of their 

 development have these glands any semblance of cells ; they have 

 a waxy homogeneous appearance, and both haematoxylin and 

 picro-carmine stain them very faintly. 



The Female Organs. 



The female genital sinus is situated posteriorly to that of the 

 male. The vagina (Fig. 6) is ampulliform. It is encircled by a 

 series of muscles and enveloped in a segregated mass of cellular 

 tissue which gives it a flocculent appearance. It is 0*4 mm. in 

 length, and has a median diameter of 0*017 mm. Its interior in 

 the proximal third, which is really the vulva, is spinous, and has a 

 transverse diameter of 0*013 mm., which contracts in impregnated 

 specimens to a minimum of 0*003 mm. At its distal end it 

 narrows and forms the vaginal canal. In stained transverse 

 sections the vulva is seen to be composed of a series of minute 

 radiating muscle fibres, which no doubt cause it to contract at 

 the time of coition. The vaginal canal (Fig. 5, vx.), on its exit 

 from the vagina, runs for a short distance ventrally to the vesicula 

 seminalis and then hangs down semicircular ly in the proglottis. 

 In its proximal portion it is somewhat attenuated, dilates itself 

 in the median third, but before making a junction with the 

 receptacnlum, it again becomes narrow and also sinuous. 



The receptaculum seminis (Fig. 5, r.s.) is a continuation of 

 the vaginal canal swollen into a large subglobular sac, and when 

 distended with, spermatozoa, after coition, has a diameter of 

 0*186 by 0*192 mm. It is situated ventrally in the distal anterior 

 third of the proglottis, the distal end of the vesicula seminalis 

 overlapping it dorsally. Its efferent duct, which forms the 

 fructifying canal, makes its exit on the ventral side, and goes 

 obliquely down the proglottis to the shell gland. The canal has 

 a diameter of 002 mm. 



The ovaries (Fig. 5, a.o. and 7^0.) are a pair of fan-like 

 organs situated medio-ventrally and in some respects similar to 



