THE GENITOURINARY APPARATUS. 



269 



The seminal granules are about one four-thousandth of an 

 inch in diameter. 



The spermatozoa are the essential elements, and consist of an 

 oval head, a body or middle piece, and a tail. 



THE PENIS is composed of three columnar bodies, two cor- 

 pora cavernosa and one corpus spongiosum, invested with skin, 

 and filled with a peculiar, vascular, sponge-like structure. 



It is attached to the pubic arch and symphysis by its root, 

 has a free expanded extremity, the glans penis, or head, and 

 an intermediary portion, the body. 



FIG. 127. 

 Vertical section of testicle. (After Gray.) 



The upper surface is the dorsum, or back. The glans is a 

 blunt, cone-like body, expanded at its base, the corona, and 

 attached by its cervix, or nock. 



The summit has a slit-like aperture, the meatus, or orifice 

 of the urethra. 



The skin adheres loosely to the organ, and has a loose, cup- 

 like fold over the glans, called the prepuce, after which ii is 

 reflected into the cervix and glans, becoming continuous with 



