SPERMATIC CORD TESTIS. 



741 



septum, numerous slender fibrous cords (trabeculoe) are given off, which pass to be 

 attached to the inner surface of the tunica albuginea ; they serve to maintain the 

 form of the testis, and join, with similar cords given off from the inner surface of 

 the tunica albuginea. to form spaces which inclose the separate lobules of the organ. 

 The mediastinum supports the vessels and ducts of the testis in their passage to 

 and from the substance of the gland. 



The Tunica Vasculosa (pia mater testis) is the vascular layer of the testis, 

 consisting of a plexus of bloodvessels, held together by a delicate areolar tissue. 

 It covers the inner surface of the tunica albuginea, sending off numerous processes 

 between the lobules, which are supported by the fibrous prolongations from the 

 mediastinum testis. 



/Structure of the Testis. The glandular structure of the testis consists of nume- 

 rous lobules (lobuli testis). Their number, in a single testis, is estimated by Berres 

 at 250, and by Krause at 400. They differ in size according to their position, 

 those in the middle of the gland being larger and longer. Each lobule is conical 

 in shape, the base being directed towards the circumference of the organ, the apex 

 towards the mediastinum. Each lobule is contained in one of the intervals between 

 the fibrous cords and vascular processes, which extend between the mediastinum 

 testis and the tunica albuginea, and consists of from one to three, or more, 

 minute convoluted tubes, the tubuli seminiferi. The tubes may be separately 

 unravelled, by careful dissection under water, and may be seen to commence 

 either by free cascal ends, or by anasto- 

 motic loops. The total number of tubes 

 is considered by Monro to be about 300, 

 and the length of each about sixteen feet; 

 by Lauth, their number is estimated at 

 840, and their average length two feet 

 and a quarter. Their diameter varies 

 from 7?ffth to y^^th of an inch. The 

 tubuli are pale in color in early life, but, 

 in old age, they acquire a deep yellow 

 tinge, from containing much fatty matter. 

 They consist of a basement membrane, 

 lined by epithelium, consisting of nucle- 

 ated granular corpuscles, and are inclosed 

 in a delicate plexus of capillary vessels. 



Fig. 372. Vertical Section of the Tes- 

 ticle, to show the arrangement of the 

 Ducts. 



In the apices of the lobules, the tubuli 

 become less convoluted, assume a nearly 

 straight course, and unite together to form 

 from twenty to thirty larger ducts, of 

 about s'oth of an inch in diameter, and 

 these, from their straight course, are called 

 vasa recta. 



The vasa recta enter the fibrous tissue 

 of the mediastinum, and pass upwards and 

 backwards, forming, in their ascent, a 

 close network of anastomosing tubes, with 



exceedingly thin parietes ; this constitutes the rete testis. At the upper end of the 

 mediastinum, the vessels of the rete testis terminate in from twelve to fifteen or 

 twenty ducts, the vasa efferentia : they perforate the tunica albuginea, and carry 

 the seminal fluid from the testis to the epididymis. Their course is at first 

 straight; they then become enlarged, and exceedingly convoluted, and form a 

 series of conical masses, the coni vasculosi, which, together, constitute the globus 

 major of the epididymis. Each cone consists of a single convoluted duct, from 

 six to eight inches in length, the diameter of which gradually decreases from the 

 testis to the epididymis. Opposite the bases of the cones, the efferent vessels 

 open at narrow intervals into a single duct, which constitutes, by its complex 



