THE ABDOMINAL WALL 241 



with the epididymis and is covered everywhere, except 

 along its posterior border, by the visceral layer of the tunica 

 vagina'lis. Its efferent ducts issue from its upper end and 

 enter the epididymis, whilst its vessels and nerves pass 

 through its posterior border. It lies somewhat obliquely in 

 the scrotum, its superior extremity being directed forwards 

 and upwards, and the left testis, as a rule, hangs at a lower 

 level than the right. Attached to the upper part of the 

 anterior border of the testis, in front of the head of the 

 epididymis one or two small pear-shaped bodies may be 

 found. They are the appendices testis, and are remnants of 

 embryonic structures. One appendix is, usually, stalked, the 

 other is smaller and sessile. 



Epididymis. The epididymis is a comma-shaped struc- 

 ture which lies along the lateral side of the posterior border 

 of the testis from its upper to its lower end. The enlarged 

 upper end of the epididymis is the caput epididymidis ; the thin 

 lower end is the cauda epididymidis, and the intervening part 

 is the corpus epididymidis. 



The caput epididymidis surmounts the superior extremity 

 of the testis like a helmet, and is attached to it both by the 

 visceral tunica vaginalis, which is continued over it, and also 

 by the ductuli efferentes, which pass from the testis into the 

 epididymis. The cauda epididymidis is fixed to the back of 

 the testis merely by the visceral tunica vaginalis and some 

 intervening areolar tissue. The body of the epididymis is 

 separated from the body of the testis by an involution of the 

 serous covering which forms the wall of the sinus epididymidis. 



The ductus deferens emerges from the inferior extremity of 

 the tail of the epididymis and then passes upwards, upon the 

 posterior margin of the testis and on the medial side of the 

 body and head of the epididymis. By this relation, the side 

 to which a given testis belongs can be readily detected. 



The vessels of the testis and the epididymis enter and 

 emerge from their posterior margins. 



Dissection. Some of the main facts relating to the structure 

 of the testis may be learned by a careful naked-eye examination 

 of its different parts. For that purpose place it in a cork-lined 

 tray and dissect it under water. Having fixed it to the bottom 

 of the tray, with pins, begin by tracing the blood-vessels into the 

 gland. As that is done, a quantity of involuntary muscular 

 tissue spread over the posterior border of the testis and the 

 epididymis becomes apparent. It is the inner muscular tunic 

 VOL. II 16 



