THE REPRODUCTIVE SYSTEM 



345 



lf 





cells (Fig. 236, c). They are believed to represent remains of the 

 Wolffian body. 



2. The Straight Tubule. — With the termination of the con- 

 voluted portion, the spermatogenic tissue of the gland ends, the 

 remainder of the tubule con- 

 stituting a complex system of , ,r-}^' ^ 

 excretory ducts. The straight 

 tubule is much narrower than 

 the convoluted, having a dia- 

 meter of from 20 to ^o/'.. It 

 is lined with a single layer of 

 cuboidal cells resting upon a 

 thin basement membrane. At 

 the apex of the lobule the 

 straight tubules become con- 

 tinuous with the tubules of the rete testis. 



3. The Tubules of the Rete Testis.— These are irregular 

 canals which vary greatly in shape and size. They are lined with a 

 single layer of low cuboidal or fiat epithelial cells (Fig. 239, C). 



Fig. 240. — Part of a Cross Section through 

 a Vas Efferens of the Human Epididymis. 

 X140. (KoUiker.) F, High columnar ciliated 

 epithelium; d, lower non-ciliatcd epithelium, 

 presenting appearance of a gland; d', the same 

 cut obliquely. 











x 



» 'm 



Fig. 241. — From Cross Section through Head of Epididymis. Ap5. (KoUiker.) 

 b, Interstitial connective tissue; c, sections through tubules of epididymis, showing two- 

 laj-ered columnar epithelium; g, blood-vessel. 



The Seminal Ducts. — While the already described straight 

 tubules and the tubules of the rete testis must be regarded as part of 

 the complex excretory duct system of the testis, there are certain 

 structures which are wholly outside the testis jiroper, which serve to 



