CHAP, vin.] ORGANS OF RESPIRATION AND SECRETION. 243 



side of the yerum montanum. It is made up of a number of small 

 follicles, which open into its excretory canals, the apertures of which 

 have just been mentioned. It is invested by a fibrous coat con- 

 taining many organic muscular fibres. It secretes a fluid of a 

 milky appearance. 



Coicper's glands (Fig. 115,^ g) are two large racemose structures 

 of firm consistency, with a thick muscular envelope, placed one on 

 each side of the urethra and a little beyond the prostate. Each 

 opens by a single duct into the urethra at the root of the penis. 

 These glands secrete a viscid fluid of unknown function. 



The scrotum is that pouch of integument which is destined to 

 contain the testes, which hang within it beneath the anus and 

 behind the pelvis. Although this pouch (the scrotum) is single 

 externally, an inner coat the dartos (consisting of vascular mem- 

 brane with organic muscular fibres) forms two pouches, one for each 

 testis. This coat is continuous with the fascia of the abdomen and 

 thigh. Within it is a layer of membrane the Dermatic fascia 

 and other envelopes of connective tissue or muscular fibres one 

 delicate layer of the latter tissue forming what is known as the 

 cmnastcr muscle. 



Each testis is also enveloped in a pouch of peritoneum, called the 

 tunica vagmalis, within which is the tunica albuginca a dense, 

 white, fibrous membrane, which immediately invests the testis itself. 



21. The TESTES are the true male sexual glands, to which all the 

 other male sexual organs are but auxiliary. Each testis is an oval 

 body, which is suspended in the scrotal chamber by a cord the 

 Dermatic cord which passes forwards and inwards through the 

 abdominal ring to the urethra. A conical, more or less separable 

 body, known as the cpididi/mis, lies dorsally and posteriorly upon 

 the testis. As it is external to the testis itself, it is not invested by 

 the tunica albuginea. One rounded end of the epididymis called 

 the ylolus major is connected with the testis by certain ducts. The 

 other more pointed end the glolus minor is only united to it by 

 connective tissue. 



At that portion of the testis which is adjacent to the epididymis, 

 the tunica albuginea is prolonged far down into the soft substance of 

 the gland, forming a septum called the mediastinum testis, or corpus 

 Hiyhmorianum, which is situated in the middle of the testis. Many 

 slender cords and lamellec of connective tissue radiate from the 

 mediastinum to the inner surface of the tunica albuginea, thus 

 dividing that portion of the gland by imperfect partitions into conical 

 interspaces, and helping to maintain the shape of the testis.^ The 

 gland is richly supplied with blood-vessels, which ramify in the 

 tunica albuginea and accompany its partitioning processes. Between 

 these membranous imperfect partitions, lies the soft proper glandular 

 substance of the testis, which consists of minute convoluted tubes, 

 called tubuli scminifcri, because they are the immediate agents in 

 seminal secretion. They are arranged in pyramidal aggregations or 

 "lobules," respectively invested by the membranous imperfect par- 



n 2 



