224 SPECIAL HISTOLOGY. 



well-known manner, forms the body and tail (globus minor) 

 of the epididymis } usually giving off at its inferior ex- 

 tremity a csecal prolongation, vas aberrans Halleri (fig. 257 i) 

 and is ultimately continuous with the spermatic duct or vas 

 deferens, which at first J — %" in diameter and convoluted, soon 

 increases, to a size of f — \" ', and becomes straight (fig. 257 h). 

 The epididymis, moreover, has an extremely delicate fibrous 

 tunic (J w ) of a greyish white colour. 



§ 198. 



Structure of the seminiferous tubes. — The seminal tubes of 

 the testis are, in proportion to their diameter, rather more 

 firmly constructed than other glandular canals and consist of a 

 fibrous membrane and an epithelium. The former, from 0*0024 

 — 0-005'", or in the mean 0-003 — 0004"' thick, composed of 

 an indistinctly fibrous connective tissue with longitudinal 

 nuclei, without muscular fibres and rarely presenting an indi- 

 cation of elastic fibrils, is tolerably firm and extensible. A 

 Fi 25g simple layer of roundish, polygonal 



cells, of 6-005 — 0-008'", occasionally 

 with an indication of a membrana 

 propria as a substratum, on the inner 

 surface of this fibrous membrane, 

 completes the vascular canal, which 

 thus obtains a wall, 0007— 0-008"' in 

 entire thickness. In younger sub- 

 jects, these cells are pale and finely 

 granular, but as age advances, a 

 continually increasing number of 

 fatty granules is collected in them, 

 whence the seminiferous tubes sometimes acquire a light yellow- 

 ish, partially brownish colour, which is manifest very frequently 

 in men even at the middle period of life, and invariably in old 

 age. The ductuli recti present the same structure as the tubes ; 

 whilst in the rete testis, no special fibrous tunic can be distin- 

 guished, the canals in this portion of the gland appearing to 

 be nothing more than cavities in the dense fibrous tissue of the 

 corpus IJighmorianum, lined by an epithelium. In the coni vas- 



Fig» 258. Portion of a spermatic tube in Man, x 350 diam. : a, fibrous coat with 

 longitudinal nuclei ; b, clear border, probably a membrana propria ; c, epithelium. 



