232 MANUAL OF HISTOLOGY. 



number of conical lobules, named the coni vasculosi, which 

 form the head of the epididymis. These tubules gradually 

 unite to form a single canal, which is much convoluted, and 

 develops an elongated body, the body and tail of the epididy- 

 mis. The convolutions becoming less and less marked, the 

 tube, increased in calibre, then leaves the testicle and ascends, 

 at first somewhat spirally, but soon after in a perfectly straight 

 course, constituting the vas defer ens. Before this duct is 

 formed, a short csecal branch, named the vas dberrans, is at- 

 tached to the tube. 



The seminiferous tubules either take their origin from blind 

 extremities or anastomoses, the former being more frequently 

 met with in children. Surrounding the tubules there is seen 

 a framework of connective tissue, which proceeds from the 

 septa. This intertubular connective tissue is distinctly lam- 

 inated, and each lamella is formed of a fenestrated endothe- 

 lial membrane, and a fenestrated connective- tissue membrane, 

 which thus constitute numerous communicating spaces, that 

 are the rootlets of the lymphatic system of the testis. The 

 number of lamellae between the seminal tubes varies, and their 

 relation to the tubes is very intimate, but depends upon the 

 amount of fluid present in the interlamellar lymph-spaces. 

 Groups of peculiar cells are found between the lamellae of the 

 intertubular connective tissue. These cells have been observed 

 by histologists, and by most are thought to be connective-tissue 

 corpuscles. Klein, however, says they are epithelial in nature, 

 and derived from the epithelial columns of the Wolffian body. 



In the meshes formed by this reticulated fibrous tissue are 

 located the seminiferous tubules, the membrana propria of 

 which is thought, on the one hand, to be structureless, or, on 

 the other, to be composed of oval, flattened corpuscles, placed 

 at regular intervals, which form an endothelial membrane. The 

 tubules are found filled with corpuscles. Those at the periphery 

 covering the membrana propria are round or polygonal in form, 

 upon transverse section. In children, the cells of the tubules 

 contain a finely granular and pale substance, but in adults 

 they are filled with yellow pigment. Two typical forms of cor- 

 puscle are observed, one with dark granular nuclei, the other 

 with bright ones that have or have not nucleoli. The number 

 of nuclei varies ; usually there are one or two ; but they may 

 reach thirty or more. Many variously formed cells are seen, 



