138 F. H. STEWAItT. 



with the receptaculnm and utei'us, and a ductus ejaculatorius 

 corresponding with the vagina. 



The testicular region occupies two thirds of the reproduc- 

 tive division of the body. It is, in addition, highly toi-tuous. 

 The wall is identical with that of the ovarian region, consist- 

 ing of an excessively flat epithelium (PI. 8, fig. 29, gic). 

 The germinal syncytium again arises from this epithelium at 

 the fundus. The vesicular nuclei of the syncytium are at 

 first scattered through the protoplasm. They soon arrange 

 themselves around the rhachis, however, measuring '003 mm. 

 in diameter. 



Further down, they invade the rhachis (PI. 8, fig. 29), 

 running in lines through it ("0043 mm.). Cell outlines begin 

 to appear in the protoplasm, leaving some residual protoplasm 

 between the cells. The rhachis ceases, and the cells lie free 

 in the lumen, packed against each other. The nuclei continue 

 to increase in size ("0064 mm.), the protoplasm is scanty. In 

 the lower reaches the protoplasm again inci'eases. The 

 spermatogonia divide by karyokinesis and form the spermato- 

 zoa, spherical bodies, "0053 mm. in diameter, showing fine 

 amoeboid processes, the nucleus represented by a single 

 chromatin granule (PI. 8, fig. 30, s.). 



The vas deferens (PI. 8, fig. 30, Y.d.) is a short muscular 

 passage from the foregoing division to the seminal vesicle. 

 Its length is about '34 mm. It is exceedingly narrow, 

 •068 mm. compared with "41 mm. of the vesicle. The wall 

 consists of a cubical epithelium with an outer muscular layer. 



The seminal vesicle (ibid., s.v.) extends through rather less 

 than one third of the reproductive region of the body. Its 

 course is straight. It is the widest portion of the genital 

 tract, '41 in diameter, the lumen distended with spermatozoa. 

 It is often constricted near the middle of its course. The 

 wall consists of an epithelial layer, which does not show cell- 

 outlines. Where the tube is distended the epithelium is 

 flat; where it is contracted the epithelium is thrown into 

 ridges. The muscular layer consists of circular fibres. 



'Ihe ductus ejaculatorius (PI. 8, fig. 31) is the shorter, 



