012 



ANATOMiT OF VERTEBRATES. 



501 



ing to, and of the vcnules returning from, the essential parts of 

 the gland. Processes of the inner layer, resolving into areolar 

 tissue, convey the vessels into the gland-substance, and partition 

 that substance into lobes: a denser layer is continued from the 

 line of the albugineal tunic perforated by the testicular vessels, 

 and projects some way into the gland : it is called ' corpus High- 

 mori,' or ( mediastinum testis,' and varies in longitudinal extent, 

 and depth of position, in different Mammals : in Man it is limited 



to the tract, fig. 501, Z>, 

 along which the reticu- 

 late ducts emerge or be- 

 come ' efferent.' The 

 cavities in which the 

 sperm-cells are deve- 

 loped, fig. 514, have the 

 form of tubes, of a dia- 

 meter of from T J--Q to -o-J-o 

 of an inch, minutely and 

 extensively convoluted : 

 from two to five of such 

 tubes, averaging; two feet 



3 O O 



in length in the human 



o 



testis, are packed into a 

 long pyramidal lobule, 

 invested by a process of 

 the inner albugineal tu- 

 nic : and the sum of these 

 lobules or packets of se- 

 miniferous tubules forms 

 the glandular part of the 

 testis, fig. 501, , a. The reticulate intercommunication mani- 

 fested in the wider spermogenous tracts of the milt of fish (vol. 

 i. p. 569, fig. 379), prevails in the more finished and thick- 

 coated seminal tubules of Mammals : and, where such become 

 free, they have blind ends. From the lobules the tubules con- 

 verge, anastomosing, but with straighter course, to the media- 

 stinum, and there form the plexus called ' rete testis,' ib. I. From 

 this the * vasa efferentia,' ib. <?, c, emerge, and enter the upper 

 end of the appended body called ( epididymis,' ib. d, y. Here the 

 convoluted disposition of the tubule is resumed, and from ten to 

 twenty groups, called ' coni vasculosi,' resembling, save in the 

 greater width and less length of the tubuli, the lobes of the testis, 

 combine to form the head or ' globus major,' d, of the epididymis. 

 By repeated anastomoses there, a single tube results, the trans- 



Glandular structure of Human testis, as shown by mercurial 

 . injection, nat. size. CCLXXII". 



