THE ACCESSORY REPRODUCTIVE ORGANS 257 



^ flf 



FIG. 69. Part of transverse section through penis of monkey. 



a, Erectile tissue ; 6, urethra ; o, artery ; (/, nerve ; e. Pacinian body ; 

 /, fold of epithelium ; </, surface epithelium. 



particularly large in the walrus. In the Cetacea the penis is often 

 of enormous size (six feet in length in some species), and terminates 

 in a point, but is otherwise normal. It can be withdrawn into the 



9 



