866 



TUB GENERATIVE AFPABATUS. 



All the portion comprised between the ischial arch and the scrotum, is 

 maintained and deeply covered by the surrounding textures, and is named 

 the fixed portion of the penis. The remainder of the organ — its anterior 



ujoiety is, on the contrary, its free portion, as it forms a detached appendage 



sustained by a cutaneous fold, the sheath (ov prepuce). 



The Fixed Portion occupies the perineal region and that between the 

 thighs, where it is enveloped by the arteries, veins, and nerves already 

 known, as well as by a large quantity of connective tissue (and the skin). 



The Free Portion is lodged in the sheath during the inactive condition 

 of the organ, but protrudes from it when in a state of erection. It is then 

 seen to be covered by a smooth, unctuous tegumentary membrane with 

 numerous papillfe, and of variable colour, though most frequently it is 



black or variegated. Its 

 '^' ■ base presents a slight circular 



7 enlargement, due to the ac- 



cumulation, beneath the 

 mucous membrane, of a small 

 annular mass of elastic and 

 contractile tissue. Its ex- 

 tremity or glans is also a cir- 

 cular enlargement limited 

 behind by a salient collar — 

 the corona glandis — which is 

 notched inferiorly, and at 

 the moment of ejaculation 

 assumes a considerable de- 

 velopment, its shape being 

 then not unlike the rose of 

 a watering-can. This en- 

 largement has for its basis 

 the terminal expansion of 

 the urethral erectile tissue, 

 and presents on its anterior 

 face : 1, In the centre, a 

 rounded prominence due to the point of the corpus cavernosum ; 2, Beneath 

 this, the urethral tube encircled by a fossa ; 3, At the bottom of the fossa, 

 and below the urethra, the orifice of a bilocular cavity — the urethral sinus, 

 which widens at the bottom, and in which accumulates sebaceous matter 

 that sometimes becomes so hard as to prevent the flow of the urine by 

 compressing the tube ; 4, Inferiorly, the suburethral notch. 



The skin covering the extremity of the penis is rich in nerves which, 

 according to Kraiise, have round dilatations \\hich he designates as 

 " terminal genital corpuscles." 



To complete the description of the penis, there only remain to be 

 described : 1, Two suspensory and retractile cords which concur, with the 

 natural elasticity of the fibrous envelope of the corpus cavernosum, to return 

 the organ to its ordinary position when the phenomenon of erection has 

 ceased ; 2, The tegumentary fold, or sheath, which envelops the free portion 

 of the penis when in its ordinary state of repose. 



A. Suspensory and Eeteaotilb Cords of the Penis. — Two in number 

 these cords arise from the lower face of the sacrum, descend as flat bands in 

 front 6i the sphincter ani, between the retractor muscle of the anus and the 

 rectum, to which they give numerous short fasciculi from their posterior 



LONSITDDINAL SECTION OF THE FREE EXTREMITY OF 

 THE horse's penis IN A RELAXED STATE. 



1, Erectile tissue of the corpus cavernosum ; 2, Urethra ; 

 3, Fossa navicularis ; 4, Urethral tube ; 5, Erectile 

 tissue of the urethra ; 6, Ditto of the glaus ; 7, 

 Corona glandis ; 8, Urethral sinus. 



