Page:Laboratory Manual of the Anatomy of the Rat (Hunt 1924).djvu/104

90 Divide the pelvic girdle along the symphysis pubis, remove the ventral part of this girdle, clear away the adjacent muscles, and expose the urethra. This runs back through the girdle ventral to the rectum. The urethra joins the penis at the posterior end of the pelvic girdle. At this place the two bulbo-urethral (Cowper's) glands pour their secretion into the urethra through a pair of long ducts. Each of these glands is ovoid in shape and about five millimeters long. It lies lateral to the rectum and just behind the posterior border of the ischium. It has been suggested that the secretion protects the spermatozoa against the harmful effects of traces of urine.

Dissect away on one side the tissues surrounding the penis. Note that it has the form of a figure 7, with the angle anteroventral. Carefully insert one blade of the scissors into the genital orifice and slit the integument lengthwise of the body. Press aside the flaps of skin and note that the terminal section of the penis, the glans, lies loose in a chamber surrounded by the prepuce or foreskin. The surface of the glans is slightly rough. Its blunt free end points backward. The two preputial glands, one on either side of the glans penis, discharge their secretion near the posterior edge of the prepuce. Dissect away the surrounding tissue and locate the duct and its opening. Each gland is dorsoventrally flattened, rounded anteriorly, and tapers back to the edge of the foreskin. Insert a fine pair of scissors into the orifice of the duct and slit it lengthwise. Note the relatively very large calibre of the duct beyond the opening, and the soapy character of the contained secretion. It has been claimed that this secretion protects the integument in this region from being injured by the excretions.

The penis is the structure which is used to carry the seminal fluid from the male to the vagina of the female.