378 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



basement membrane inward toward the lumen 

 of the tube. They give off lateral processes that 

 form a reticulum about groups of young spermatozoa, 

 to which they give both support and sustenance, 

 according to the views of some authors. 2. Within 

 the first layer there are one or two rows of large cells 

 with large deep -staining nuclei. These are the 

 spermatocytes. The latter multiply rapidly and 

 continually to form, 3, spermatoblasts or sper- 

 matids. The spermatids are small spherical cells 

 and each one in due time develops into a spermato- 

 zoon. The latter ripen regularly in groups which 

 seem to cluster about individual sustentacular cells. 

 The nucleus of the spermatids elongate and each 

 little spherical cell gradually assumes the form of a 

 mature spermatozoon. The different stages in this 

 development can be worked out by a study of the 

 spermatids as seen in the different tubules. In the 

 cross section of a single tubule all the spermatids 

 will be in the same stage of development. The 

 spermatozoa when mature are crowded into the 

 lumen of the convoluted tubules, where they mix 

 with a viscid secretion which probably comes from 

 the epithelial wall. The convoluted seminiferous 

 tubules end blindly near the surface of the testis, 

 where they are also said to anastomose with each 

 other. In the other direction, each tubule becomes 

 straight and forms the tubuli recti, which approach 

 the mediastinum and function as excretory ducts. 

 These erect tubules anastomose to form the rete 

 testis. 



Interstitial Elements of the Testis. Like any other 



