CHAPTER VII 



THE ACCESSORY REPRODUCTIVE ORGANS OF THE 

 MALE AND THE MECHANISMS CONCERNED IN 

 INSEMINATION 



" Mais, par oe moyen de propagation seminale, demeure es enfans oe qu'estoit 

 de perdu es parens et es nepveux ce que' d^perissoit es enfans, et ainsi 

 sucoessivement." — Rabelais. 



A BRIEF description of the mammalian testis has already been given 

 in a chapter on the physiology of the spermatozoon (p. 159). It 

 remains, however, to state what is known regarding the functional 

 relations of the accessory male organs, and to refer incidentally to 

 the homologous structures in the female. 



After traversing the tubules of the rete testis the spermatozoa, 

 swimmiilg in the seminal fluid, make their way into the vasa efferentia, 

 which open into thet;anal of the epididymis. The vasa efferentia in 

 man are about twenty in number. Before passing into the epididymis 

 they become convoluted, forming the coni vasculosi. Both the vasa 

 efferentia and the tube of the epididymis contain smooth muscular 

 fibres in their walls. They are lined internally by columnar epithelial 

 cells provided with long cilia which assist the muscles in expelling 

 the semen. 



Passing away from the epididymis, and in continuation with its 

 canal, is the vas deferens, which is nearly two feet long in the human 

 subject, and has an average diameter of about one-tenth of an inch. 

 It possesses a plain muscular wall, consisting of an outer layer of 

 longitudinal, a middle of circular, and an inner of longitudinal 

 muscles. On the inside of the muscles there is a mucous coat lined 

 by a columnar epithelium, which is not ciliated.^ 



A branch from one of the vesical arteries accompanies the vas 

 deferens, and eventually enters the testis, where it anastomoses 

 with the spermatic artery. The vas deferens, near its termination, 



' The epithelium of the vas in some animals (rat) is apparently ciliated. 

 Arising from the lower part of the epididymis, or from the vas deferens 

 close to its commencement, is a long narrow diverticulum which ends blindly. 

 This is the vas aberirans. It is probably a vestigial structure. A few small 

 convoluted tubes, situated near the head of the epididymis and representing 

 vestiges of part of the "Wolffian body, are called the paradidymis or organ of 

 Giraldfes. The innervation of the vas deferens is described below (p. 269). 



