THE MALE GENITAL ORGANS. 



367 



bers of convoluted and blindly ending canaliculi are frequently 

 found imbedded in the connective tissue around the epididymis. 

 These constitute the paradidymis, or organ of Giraldes. 



The blood-vessels of the testis spread out in the corpus High- 

 mori and in the tunica vasculosa of the connective-tissue septa and 

 of the tunica albuginea, their capillaries encircling the seminal tu- 

 bules in well-marked networks. 



The lymphatic vessels begin in clefts in the tunica albuginea and 

 in the connective tissue between the convoluted tubules. They con- 

 verge toward the corpus 

 Highmori and pass 

 thence to the spermatic 

 cord. 



Retzius (93) and Tim- 

 ofeew (94) have described 

 plexuses of norimedul- 

 lated, varicose nerve-fibers 

 surrounding the blood- 

 vessels of the testis. From 

 such plexuses single 

 fibers, or small bundles of 

 such, could be traced to 

 the seminiferous tubules, 

 about which they also 

 form plexuses. Such 

 fibers have not been 

 traced into the epithelium 

 lining the tubules. In 

 the epididymis Timofeew 

 found numerous sympa- 

 thetic ganglia, the cell- 

 bodies of the sympathetic 

 neurones of which were surrounded by pericellular plexuses. In 

 the wall of the vas epididymidis and the vasa efferentia were observed 

 numerous varicose nerve-fibers, arranged in the form of a plexus, 

 many of which seemed to terminate on the nonstriated muscle cells 

 found in these tubes. Some of the nerve-fibers were traced into the 

 mucosa, but not into its epithelial lining. 



Fig. 296. Section of dog's testis with in- 

 jected blood-vessels (low power) : a, Seminifer- 

 ous tubule ; b, connective-tissue septum ; c, blood- 

 vessel. 



3. THE EXCRETORY DUCTS. 



The vas deferens possesses a relatively thick muscular wall, con- 

 sisting of three layers, of which the middle is circular and the other 

 two longitudinal. The subepithelial mucosa is abundantly supplied 

 with elastic fibers and presents longitudinal folds. The lining epi- 

 thelium is in part simple ciliated columnar and in part stratified 

 ciliated columnar, with two rows of nuclei. The cilia are, however, 

 often absent, beginning with the lower portion of the vas epidi- 



