DEVELO^ME^^T OF THE EPIDIDYMIS AXD YAS DEFEEEXS. S-25 



dymis receives an explanation from that circumstance. As to the coni vasculosi 

 in the upper part of the epididymis, it has been customary to regard them as 

 produced by a transformation of the tubes and duct in the upper part of the 

 Wolffian body, according to the views most fully given by Kobelt ; but, accord- 

 ing to the more recent observations of Banks, the origin of the coni vasculosi is 

 most jn'obably due to a process of development occm-ring in a new stnictiure or 

 mass of blastema which had been jireviously observed by Cleland, and which is 

 foiTued in connection with the upper end of the "Wolffian body, and close to the 

 Miillerian duct. "Within this blastema Cleland showed that the tubes of the 

 efferent seminal vessels and the coni vasculosi, together with the tube which 

 connects them, are formed anew, while the tubes of the lower primordial -kidney 

 part of the "Wolffian body are undergoing an atroi^hic degeneration. This has 

 been confirmed by the detailed observations of Banks, who has further shown 

 the continuity of their uniting tube with the "\Yolffian excretory duct. 



According to this view, the caput epididymis must be regarded, not simply as a 

 conversion of the ujiper part of the "Wolffian body, but rather as a new forma- 

 tion, or superinduced development of tubes in blastema connected with it. 



The coni vasculosi, so fonned, become connected with the body of the testicle 

 by means of a short straight cord, which is afterwards subdivided into the vasa 

 efferentia. The peritoneal elevation descending from the testis towards the lower 

 extremity of the "Wolffian body, is the upper part of the plica gubernatrix, and 

 becomes shortened as the testicle descends to meet the lower end of the epidi- 

 djTiiis ; the peritoneal elevation which passes do'OTi into the scrotum, and is 

 continuous with the other, is the more important part of the plica gubernatrix, 

 connected with the gnbernactilum testis. The spennatic arteiy is originally a 

 branch of one of those which go to the "Wolffian body, and ascend from the 

 surface of the Wolffian body to the upper part of the testis, along the ligaments 

 connecting them ; but, as the testis descends, the artery lies entnely above it, 

 and the secreting substance of the Wolffian body remains adherent to it ; and 

 hence it is that the organ of Gii-aldes, which consists of persistent "\\'olffian 

 tubules, is found in a position superior to the ei^ididymis. (For a fuller account 

 of this subject the reader is referred to Banks "-On the Wolffian Bodies," Edin 

 18G-i.) 



Fig. 616. YiEW FROM BEFORE OF Fig. 616. 



THE Adttlt Testis and Epididt- 

 Mis (from Farre, after Kobelt). 



a, a, convoluted tubes in ■ the 

 head of the epididymis developed 

 from the upper part of the Wolffian 

 body ; b and /, hydatids in the head 

 of the epididymis ; c, coni vasctdosi ; 

 (/, va.sa aberrantia ; /(, remains of 

 the duct of ]\Udler ■with i, the 

 hydatid of IMorgagni at its upper 

 end ; /, body of the testis. 



The Descent of the Testicles. 



— The testicles, which are origin- 

 ally sitixated in the abdominal 

 cavity, pass down into the 

 scrotum before birth. The testicle 



enters the internal inguinal ring in the seventh month of foetal life : by the end 

 of the eighth month it has usually descended into the scrotum, and, a little time 

 before birth, the naiTow neck of the peritoneal pouch, by which it previously 

 communicated with the general pei-itoneal cavity, becomes closed, and the pro- 

 cess of peritoneum, now entu-ely shut off from the abdominal cavity, remains as 

 an independent serous sac. The peritoneal pouch, or processus vaginaliB, which, 

 passes do-mi into the scrotum, precedes the testis by some time in its descent, 

 and into its posterior part there projects a considerable columnar elevation 



