274 



HISTOLOGY. 



The superficial cells show alternating areas of mature and immature 

 spermatozoa. In cross sections all the superficial cells may be of one 

 stage, which differs from that of the adjoining tubule (Fig. 305). Toward 

 the periphery of the testis the convoluted tubules (140 /* in diameter) 

 present many loops and they may anastomose forming a network. Blind 

 endings are also observed, and investigators disagree as to the nature of 

 the usual termination. As they pass toward the epididymis they receive 

 branches at acute angles and their windings diminish. Sexual cells dis- 

 appear, leaving only the sustentacular cells in the form of a simple 



If 



Ductus 

 deferens. 



Blood vessels. 



Epididymis. 



Mediastinum, 

 containing the 



rete testis. 

 Straight 

 tubules. 



Septula. 



Lobules, con- 

 sisting of con- 

 voluted tubules. 



Tunica 

 vasculosa. 



Tunica 



albuginea. 



FIG. 311. CROSS SECTION OF THE TESTIS OF A CHILD AT BIRTH. X 10. 



columnar epithelium. This flattens abruptly to form the lining of the 

 straight tubules. 



A distinction between the rete and straight tubules seems superfluous 

 histologically since both are lined with a simple epithelium of low cells. 

 In some places these are very flat, suggesting endothelium; in others they 

 are columnar. The characteristic dilatations of the rete tubules are shown 

 in Fig. 310. They contain spermatozoa and immature sexual cells together 

 with pigment granules and broken down cells. 



Connective tissue of the testis. The rete possesses no basement mem- 



