CH. LVII.] THE TE8TES. 795 



karyokinetic figures in their nuclei, indicating they are about to 

 divide. Some of these cells are longer than the rest, and project 

 into the cavity of the tube, where they form a connection with 

 groups of developing spermatozoa. They are called sustentacular 

 cells. 



Next to the lining epithelium is a zone of larger cells, two or 

 three deep. These are called spemnatogenic cells ; the nuclei 

 of nearly all of these show karyokinetic figures. Most internal 

 of all are a large number of small cells with circular nuclei. They 



Fig. 606. Dissection of the base of the bladder and prostate eland, showing the vesiculse 

 seminale* and vu-sa deferentia. a, lower surface of the bladder at the place of re- 

 flexion of the peritoneum ; b, the part above covered by the peritoneum ; i, left vas 

 deferens, ending in r, the ejaculatory duct ; the vas deferens has been divided near i, 

 and all except the vesical portion has been taken away ; , left vesicula seminalitt joining 

 the same duct ; i , the right vaw deferens and right vesicula wmiimlis. which has 

 been unravelled ; p, under side of the prostate gland ; m, part of the urethra ; u ti, the 

 ureters (cut short), the right one turned aside. (Haller.) 



are called spermatoblasts. In other tubules the spermatoblasts 

 may be seen in various stages developing into spermatozoa ; they 

 become elongated : their nucleus is at one end, and from the 

 other a tail-like process grows ; groups of the young spermatozoa 

 apply their heads to the sustentacular cells, from which they 

 derive nutriment ; their tails project into the lumen ; they even- 

 tually become free. 



The straight tubules consist of bawement membrane and lining 

 cubical epithelium only. 



The interstitial connective tissue of the testis is loose, and 



