NORMAL HISTOLOGY. 



with flattened cells, called the rete testis. The chan- 

 nels of the rete testis are continuous with several 

 tubules, which, passing upward and backward, be- 

 come very much convoluted, and form a number of 

 conical masses coni vasculosi which largely consti- 

 tute the head of the epididymis. The tubules of 

 the coni vasculosi gradually unite as they descend 

 to form a single canal, which, with numerous wind- 

 ings and contortions, constitutes the body and tail 

 of the epididymis, and finally becomes continuous 

 with a straight, thick-walled ascending tube the 

 vas. defer ens. 



The seminiferous tubules, which chiefly concern 

 us here, lie imbedded in loose, delicate, lamellated 

 connective tissue, which is abundantly supplied with 

 blood-vessels, and contains many cells ; among the 

 ordinary connective-tissue cells of various forms, 

 large granular, often pigmented cells are not infre- 

 quently seen lying singly or in groups, and some- 

 times in rows along the blood-vessels ; their nature 

 and significance are still doubtful. The tubules 

 have a distinct membrana propria, and are lined 

 with several layers of cells piled irregularly over one 

 another, which differ in form under different circum- 

 stances, and sometimes in different parts of the same 

 gland. 



In a tubule which is not producing spermatozoa, 

 the outer row of cells those lying upon the mem- 

 brana propria are large, granular, well-defined, nu- 



