SEMINIFEROUS TUBULES. 173 



and conducting, called the seminiferous tubules, supported in 

 a connective-tissue framework. It is well supplied with 

 bloodvessels, and also has lymph-channels; its nerve-supply is 

 inconspicuous and obscure. 



The surface of the testis is covered with a serous membrane, 

 the visceral layer of the tunica vaginalis ; this sac is invagi- 

 nated over the testis from behind, leaving a hiatus or hilum 

 for the entrance of the elements of the spermatic cord. 



The sustentacular connective tissue of the testis consists of 

 the tunica albuginea, mediastinum testis, and interlobular and 

 intertubular tissue. 



The tunica albuginea is a dense fibrous capsule enveloping 

 the organ, lying underneath and merging into the visceral 

 layer of the tunica vaginalis. At the posterior part of the 

 testis the tunica albuginea is thickened, forming a longitudinal 

 ridge or mass called the mediastinum testis, or corpus of High- 

 more; this contains a system of communicating spaces, the 

 rete testis. 



In infancy numerous well-marked fibrous partitions (inter- 

 lobular septa) radiate from the mediastinum testis and, extend- 

 ing across toward the tunica albuginea opposite, divide the 

 testicle into a number of conical compartments or lobules, 

 with their apices directed toward the mediastinum. 



The adult and fully developed testicle, however, is often 

 less completely and less conspicuously divided into lobules, 

 the interlobular septa being occasional rather indefinite fibrous 

 laminae, a little thicker than the intertubular septa. 



Lining the interlobular septa and the inner surface of the 

 tunica albuginea is the tunica vasculosa, a layer of areolar 

 tissue containing abundant bloodvessels. 



The individual seminiferous tubules are separated from one 

 another by the intertubular tissue, thin connective tissue parti- 

 tions containing capillaries and providing basement-membranes 

 for the tubules. In places within the intertubular tissue are 

 situated groups of large spheroidal epithelioid (?) cells, inter- 

 stitial cells. 



The seminiferous tubules exhibit several divisions, which are, 

 from their beginning onward, as follows : convoluted tubules, 

 tubuli recti, rete testis, vasa efferentia, and epididymis. The 

 convoluted portions generate the spermatozoa, the remaining 



