CHAP. i.J MALE ORGANS. 1503 



The testis proper is surrounded by a lamellated capsule of 

 connective tissue, the tunica albuginea. On the outside, this cap- 

 sule is further covered by the tunica vaginalis, the visceral layer 

 of the lining of the serous cavity in which the testis lies ; this, like 

 other serous layers, such as that of the peritoneum, consists of a 

 connective tissue basis (closely adherent to the capsule beneath), 

 covered with epithelioid plates. From the capsule numerous septa, 

 like the capsule lamellated in texture, radiate through the body of 

 the testis converging to the hind and upper part of the oval, where 

 they join into an irregular network, the corpus Highmori. The 

 more or less conical converging chambers defined by these septa 

 are occupied by groups of relatively large tubules, the seminiferous 

 tubules, which may be compared to the uriniferous tubules of the 

 kidney, except that they are much larger, and have a very wide 

 lumen. Beginning at the periphery of the testis, and frequently 

 anastomosing at their commencement, the tubules, supported by 

 a scanty reticulum of connective tissue, pursue a somewhat 

 tortuous course converging to the corpus Highmori. Each semi- 

 niferous or seminal tubule consists of a basement membrane lined 

 by a special epithelium, whose characters we will discuss presently. 



As they approach the corpus Highmori, the tubules somewhat 

 suddenly change in character; they become narrower, their epi- 

 thelium is reduced to a single layer of low cubical cells, and their 

 course becomes straight ; they are now called vasa recta. In the 

 corpus Highmori itself these vasa recta anastomose freely with 

 each other and form a network of irregular but narrow passages, 

 lined with a single layer of flat squamous epithelium, the basement 

 membrane being lost or fused with the connective tissue of the walls. 

 From this network, which is called the rete vasculosum or rete testis, 

 there issue on the farther side a number (twelve to twenty) of 

 ducts, with relatively thick walls, the vasa efferentia. The ter- 

 minal portion of each vas efferens is coiled up into a conus vas- 

 culosus, and the several coni vasculosi join at intervals to form 

 a single duct, the epididymis which, though of great length, is 

 coiled up into the compact mass spoken of above as forming a cap 

 to the testis proper. When it issues from the coil the duct 

 receives the name of vas deferens, and leaving the scrotum in 

 which the testis hangs pursues its course to the penis. 



The vasa efferentia and the epididymis which they by joining 

 form, in contrast to the channels of the rete testis have well- 

 defined walls of connective tissue, strengthened by muscular fibres, 

 disposed for the most part circularly, and are lined by columnar 

 epithelium cells, each of which bears a tuft of cilia. If the tubes 

 be examined along their course from the rete to the end of the 

 epididymis, it will be seen that the walls become stouter as the 

 tube increases in size, and that the epithelium cells become con- 

 spicuously tall, with cilia of remarkable length. The walls of the 

 vas deferens are still stouter, an inner circular and an outer longitu- 



