242 THE PHYSIOLOGY OF REPRODUCTION 



and in man lies hidden by the prostate, is probably almost or quite 

 functionless, but it has a few very small glands which open into its 

 cavity. In some animals — such as the goat, for example — it is of 

 comparatively large dimensions, the upper part being divided into 

 two horns. In connection with it is a structure corresponding to the 

 hymen of the female. On the floor of the prostatic portion of the 

 urethra is an elevation of the mucous membrane and underlying 

 tissue, known as the crista urethra or caput gallinaginis. This 



Pig. 64. — Transverse section through, commencement of vas deferens. 

 (After Klein, from Schafer.) 



a, Epithelium ; 6, mucous membrane ; c, d, e, inner, middle, and outer 

 layets of muscular coat ; /, internal cremaster muscle ; g, blood-vessel. 



eminence (which contains erectile tissue) serves when distended with 

 blood to prevent the semen from passing backwards to the' bladder, 

 and mingling with the urine in the process of emission. It is 

 assisted in this function by the contraction of the sphincter of the 

 bladder. 



The urethra in the female corresponds to that part of the male 

 urethra which is anterior to the openings of the ejaculatory ducts.' 

 It is lined with a stratified scaly epithelium, like that Of the vagina.^ 

 Communicating with the female urethra are two complex tubular 

 glands known as the glands of Skene. Their ducts open very close 

 to the urethral aperture. 



' See footnote on p. 71 for interrelationships of female organs. 



