THE ANATOMY OP ONCHOLAIMUS VUI-GAIilS, BAST. 129 



opens out although its lumen is not so wide as that of the 

 uterus. Shortly after its commencement, where the lumen 

 begins again to widen out, a narrow canal passes through its 

 dorsal wall and opens into the intestine. This is the gon- 

 euteric canal. 



The wall of the vngina consists of three layers — an internal 

 epithelium, a middle muscular, and an outer glandular layer. 



The epithelium is composed of cubical cells, the walls of 

 which are thick and consist oi:" specially condensed protoplasm. 

 Within these walls the protoplasm does not stain, so that the 

 nucleus appears to lie in a vacuole. The muscular layer is 

 thick, the fibres circular. Where the two vnginjB meet (PI. 8, 

 fig. 24) the fibres pass outwards to the body- wall, forming a 

 longitudinal layer around the short common terminal portion 

 of the tube. It is difiicult to distinguish any definite epithelial 

 lining in this portion, but a fine film o£ cuticle is invaginated 

 through the external aperture. The aperture is surrounded by a 

 sphincter internal to the longitudinal fibres. 



The vaginal and vulvar glands consist of cells lying in the 

 body space. Around the first half of the vagina they form a 

 single layer, and as they are pear-shaped give the appearance 

 of a rosette in transverse section. I have not been able to 

 demonstrate any openings from these cells into the lumen of 

 the vagina, but from the definiteness of their arrangement it 

 seems natural to suppose that their secretion is discharged 

 into the vagina. Beyond the middle of the vagina the cells 

 begin to arrange themselves around the vulva, and processes 

 pass from them to a circle of minute pores surrounding this 

 aperture (PI. 8, fig. 24, vug. a]}.). 



The vagina always contains masses of spermatozoa (ibid., s.). 

 Near the vulva these are spherical, with stellate nuclei, but 

 higher up at the uterine end they become elongated and the 

 nucleus almost thread-like. 



Fertilisation must presumably take place in the vagina 

 during the passage of the ova. It is somewhat peculiar that 

 spermatozoa do not find their way up to a level at which the 

 ova are without their shell, as occurs in the forms described 



