XXX V] TISSUES OF REPRODUCTION 281 



the greater part of the testis and firmly attached to the 

 underlying tunica albuginea. 



The tunica albuginea, the thick connective tissue 

 coat of the testis. 



The mediastinum (corpus Highmori), a patch of 

 connective tissue seen near the centre of the section ; 

 bands of connective tissue radiate from it towards the 

 tunica albuginea, but most become thin or branch on 

 their way, so that the division of the testis into lobules 

 is very imperfect. 



The tubuli seminiferi, contorted tubes, surrounded 

 by a little fibrous tissue and a considerable number of 

 polygonal cells, the interstitial cells. (The interstitial 

 cells are absent in some animals, as the rat ; cp. 2, d.) 



The convoluted tubes unite near the mediastinum, 

 forming the straight tubes. 



The rete testis, into which the straight tubes 

 open ; note the irregular and anastomosing spaces. 



The efferent tubules (vasa efferentia), rather large 

 tubes arising from the rete (not present in every 

 section). 



The conspicuous tubes of the epididymis with large 

 lumina. 



6. Observe under a high power 



The connective tissue structures and the interstitial 

 cells mentioned under a. 



The tubuli seminiferi, consisting of basement mem- 

 brane and several layers of cells. (The characters of 

 the cells will be better seen in 9.) 



The straight tubes, lined by a single layer of cubical 

 or flattened cells. 



