266 HUMAN ANATOMY. 



diverge, and with similar cords from the tunica albuginea serve 

 to maintain ihe shape of the gland and divide it into lobules. 



The tunica vasculosa (pia mater testis) lies within the 

 tunica albuginea, and is the source and termination of the blood- 

 vessels to the secretory substance of the gland, resembling the 

 pia mater of the brain. 



The glandular structure of the testis is divided into several 

 hundred (two hundred and fifty to four hundred) pyramidal 

 lobules (lobuli testis), each one of which consists of from one 

 to three tubuli seminiferi. 



At the conical extremity of the lobules the tubules end in 

 straight tubes, vasa recta, which enter the mediastinum to form 

 the plexus retiformis. From the upper part of this the vessels 

 unite into from twelve to twenty vasa efferentia, which pass out 

 of the testicle to the epididymis. Within the epididymis these 

 efferent canals form a series of spermatic cones, the coni vasculosi. 

 These end in a coarse, convoluted tube, about twenty feet in 

 length, forming the body and tail of the epididymis, and ending 

 in the spermatic duct, or vas defer ens. These tubes are lined 

 with columnar ciliated epithelium. 



The vas aberrans of Haller is a spermatic cone joining the 

 epididymis, but unconnected with the testicle. 



The hydatids of Morgagni are one or two pediculated bodies 

 attached to upper part of testis or head of epididymis, and sup- 

 posed to be the remains of Miiller's duct. 



Structure of the Tubules. The tubuli seminiferi are minute 

 convoluted tubules, closed at one extremity, consisting of a hya- 

 line membrana propria lined with several layers of epithelial 

 polyhedral cells, the seminal cells, from which the seminal or 

 spermatic fluid is directly elaborated. 



These cells undergo a process of indirect division to form 

 the spermatoblasts, which are arranged into bundles, and are con- 

 verted into spermatozoids, the nuclei becoming the head, and 

 the tail, or ciliary appendages, being afterward developed. These 

 cells are constantly cast off and replaced. 



Descent of the Testes. In early fcetal life the testes are 

 placed at the back part of the abdomen, below and in front of 

 the kidneys, and behind the peritoneum. 



About the third month a peculiar structure, the gubernacu- 

 lum testis, appears, attached to the lower end of the epididymis, 

 and extending as a cord to the bottom of the scrotum. It is 

 supposed to cause the descent of the testicle. It reaches its full 

 development between the fifth and sixth month, at which time 

 the testicle reaches the iliac fossa. It enters the internal abdom- 

 inal ring by seventh month, and the scrotum by the eighth 



