The testes are of a flattened, oval form, smooth and regular on their flat surfaces, and on one extremity, but rendered unequal at the other extremity, and at one side, by an irregular convoluted body, called epididymis. They are of a grayish or yellowish colour, and a pretty firm consistence. They are situated within the bag called scrotum, in such a manner, that their atlantal extremi ties project a little .sternal, while their sacral extremi ties point a little Arvid. They are separated from each other by a doubling of the cellular substance within the scrotum, and they are each inveloped in distinct mem branes. The most peripheral of these membranes is a doubling from the peritoneum that lines the belly, into which cavity it may be readily traced. This is called the vaginal coat (tunica vaginalis). It adheres closely to the next membrane of the testis, only in a line on the dorsal side, being in every other part perfectly free, and so roomy, that the testis can easily IlluVe W11.11111 The next membrane appears, in toe adu,t, to be only a reflection front the preceding, over toe bony of the testis, like the peripheral coat of the heart reflected Iron' the pericardium; though, as will he presently explained, it was originally formed by a separate and very distant por tion of tile perituncum. It is thick, strong, inelastic, and of a shining white colour, and closely invests the body of toe testis, giving it a smooth and regular appearance. It also invests the epididymis, closely connecting it with the body of the testis, except in one part, where it often passes between them. This coat is called tunicu alb aginca.
The substance of the testes is extremely vascular, and is composed partly of ramifications of arteries and veins, and partly of numerous small tubes, in which the seminal fluid is contained. The extreme branches of the arteries are collected within the body of the testes, into little tortuous bundles, separated from each other by partitions of cellular substance, and extending in a radiated form from the dorsal line to which the vaginal coat is fixed, luripherad towards the !Judea albuginea. The seminiferous tubes take their origin from these bundles of arterial branches, and gradually form a num ber of distinct canals, which, emerging from the body of the testis near its at lantcd extremity, unite in a larger tube that becomes extremely convoluted, and forms what is called the head of the epididymis. The whole of this irregular projecting body is merely a continuation of the common seminal canal, which, running sacral along the edge of the testis, is reflected near the sacral extremity of that body, and forms what is called the vas drferens.
This continuation of the seminal tube now expands, and becomes nearly straight, till it emerges from the scrotum, and enters the pe/vis, when it takes a curved direction across the side of the urinary bladder, and passing along the dorsal part of this receptacle, termi nates at its neck, between the seminal vesicle and the prostate gland.
The testes are well supplied with arteries, nerves, and absorbents. Their arteries are called spermatic;
they come off from the sternal side of the aorta, at a very acute angle, a little above the origin of the inferior me senteric artery (see Plate XIX. Fig. 10. N.); and they run in a very serpentine direction, till they enter the body of the testis. The sp...rmatic veins are very large and form a plexus that is closely connected to the arte ries. The spermatic artery and vein on each side are intimately connected by cellular substance, both with each other, and within the peg' is with the vas cl.fcr..as, thus forming a cord of considerable size, called the sper matic cord. Along this cord run the nervous filaments that supply the testis and the absorbent vessels that ori ginate in that gland. The spermatic cord passes through the ring of the external oblique muscle of the abdomen, and is covered by fleshy fibres that form what. is called the CrenlaS'er muicle of the tests. This muscle, be sides being connected wIth the peripheral surface of the spermatic cord, near the body of the t-stis, is at tached to the sk'n of the scrotum and to the central surface of that tendinous, expansion from the external obliAte muscle that forms the sternal I.order or the abdominal and is called the (•rural arch, or Pon part's ligament; thus s-rvillg bot'i to the tes tis, and, by the contraction of its fibres, to raise it atlantad.
The scrotum, or bag that contains the testes, is merely a continuation of the common inu guments, differing Iron' them only in the looseness of its texture, and in the redness :old fibrous appearance of the cellular mem brane that corms its central suffice. On its peripheral surface, in the direction of the 11112sial line, there is a slight elevation or the skits, called raphe, extending to wards the anus, across that part of the integuments called perineum.
The organs called seminal ve6icles arc united at their sacral anti sternal extremitiesovhere they join Lilt: neck of the bladder, but gradually diverge as they proceed do•sad and at la n tad, on the sides of that receptacle. They are membranous cavities, formed each of a very convoluted tube, that has several irregular processes, and is surrounded by much tough cellular substance. Within this cellular menibraue appears the proper coat of the vesicles, which is white and firm, and lined by a tine membrane, which appears to be a continuation of the mucous membrane that lines the vas del rens and the urethra, and is reflected into ralllICFOUS finely. This membrane is provided with mucous follicles that secrete the usual mucous fluid. 'clic cavities of the two semi nal vesicles are separated from each other at the neck of the bladder by a small projection called vcrumonta num, or caput ,g-allinaginis; and on each side of this pro jection is a tube that forms a canal leading from the seminal vesicles and vas (tiff rens, and opening into the commencement of the urethra at the sacra/ and dorsal part of the neck of the bladder.