346 



THE ORGANS 



transmit the secretion of the testis, and are known as the seminal 

 ducts. On leaving the testis these ducts form the epididymis, after 

 which they converge to form the main excretory duct of the testis, 

 the vas deferens. 



The Epididymis. — From the tubules of the rete testis arise from 

 eight to fifteen tubules, the vasa ejferentia, or efferent ducts of the 

 testis (Fig. 233, e). Each vas efferens pursues a tortuous course, is 

 separated from its fellows by connective tissue, and forms one of the 

 lobules of the head of the epididymis. The epithehum of the vasa 

 efferentia consists of two kinds of cells, high columnar ciliated cells 

 (Fig. 240, F), and, interspersed among these, low cuboidal non- 

 ciliated cells (Fig. 240, d). Occasionally some of the high cells are 

 free from cilia and some of the cuboidal cells may bear cilia. The 

 cuboidal cells He in groups between\groups of the higher cells, often 



giving the appearance of crypt- 

 like depressions. These have 

 been referred to as intraepithelial 

 glands. They do not, however, 

 invaginate the underlying tissues. 

 The epithelium rests upon a base- 

 ment membrane, beneath which 

 are several layers of circularly 

 disposed smooth muscle cells. 



The vasa efferentia converge to 

 form the vas epididymis (Fig. 241) . 

 Here the epithelium is of the 

 stratified variety, there being two 

 or three rows of cells. The sur- 

 face cells are narrow, liigh, and 

 ciliated, and their nuclei are 

 placed at dift'erent levels (Fig. 

 242). The ciha are long and each cell has only a few ciha. The 

 deeper cells are irregular in shape. The basement membrane and 

 muscular layer'- a'-e the same as in the vasa efferentia. As the vas 

 deferens is approached the muscular coat becomes thickened, and 

 is sometimes strengthened by the addition of scattered bundles of 

 longitudinally disposed cells. 



The Vas Deperens. — The walls of the vas deferens consist of 



four coats — Jnucosa, submucosa, muscularis, and fibrosa (Fig. 243). 



The mucosc is folded longitudinally, and is composed of a stroma 



Fig. 242. — Vertical Section through 

 Wall of Tubule of Epididymis. X700. 

 (Kolhker.) (Fig. 241 more highly magni- 

 fied.) b, Connective-tissue and smooth 

 muscle cells; e, basal layer of epithelial 

 cells; /, high columnar epithelial cells; p, 

 pigment granules in columnar cells; c, 

 cuticula; h, cilia. 



