868 



TEE GENERATIVE APPARATUS. 



Fi?. 404. 



a short, but very salient veru montanum, wHch divides into two mucous columns, that 

 gradually subside posteriorly ; 2, Towards the ischial arch, a valve whose free border, 

 directed downwards, covers a cul-de-sac about 3-4ths to 1 inch deep. 



The structure of the urethra is also different. The walls of the membranous portion 

 are thicker than in the Horse; they have a layer of erectile tissue, and a WUson's 

 muscle very thick below and laterally, and whose fibres are inserted in the middle of 

 the upper surface, into an aponeurotic raphe. 



At the ischial arch, when the canal bends downwards, the spongy tissue becomes 



more abundant to form the hulb of the 

 urethra ; Imt the prominence at this point 

 is chiefly due to the accelerator urinse, 

 as is shown in figure 404, c, 4. This 

 muscle is extremely powerful, but it 

 soon ceases beneath tlie ischial arch. 

 The iransversus perinei is as strong as in 

 Solipeds. 



Glands annexed to the urethra. — 

 Coioper's glands are absent. The pros- 

 tate gland is not voluminous, and forms, 

 at the commencement of the urethra, 

 a little transverse yellow mass, beneath 

 which pass the vasa deferentia ; it also 

 lies beneath Wilson's muscle, and is 

 prolonged for some distance on iihe mem- 

 branous portion of the urethra. 



Penis. — In tlie Bull, the penis is long 

 and thin, and carried well forward be- 

 neath the belly. It is inclosed at the 

 perineum in an aponeurotic sheath, 

 which is covered by the ischio-tibinl 

 muscles. This sheath is double, its 

 superficial layer being continuous with 

 the dartos, and has the same physical 

 characters ; the deep layer is thin, white, 

 and inelastic. 



In front of the pubis, the penis des- 

 cribes two successive curves — the 8 of 

 the penis — the first with its convexity 

 forwards, the second backwards. It is 

 at the second curve that the suspensory 

 lifjaments join the penis, and continue 

 along its sides to its extremity. 



The free portion of the organ, very 

 tapering, is covered by a fine, papil- 

 lated, very sensitive, rose-coloured 

 mucous membrane. 



It is lodged in a narrow sheath that 

 advances much more forward beneath 

 the abdomen than in Solipeds, and has 

 at its opening a bunch of long stiff hairs. 

 This cutaneous sheath is moved by four 

 subcutaneous muscles : two posterior or 

 retractors (Fig. 405, 2) which draw the 

 sheath backwards, and concur in ex- 

 posing the penis at the moments of its 

 erection ; and two anterior or protractor 

 muscles (Fig. 405, 1) which carry the 

 sheath forward to its former position. 

 The latter are found in the Cow, and do 

 not appear to be of any use. 



The two constituent portions of the 

 copulatory organ are not joined in the 

 same manner as in Solipeds, the channel 

 for the lodgment of the urethra being 

 transformed into a complete canal by a narrow layer of the fibrous envelope of the corpus 



SECTIONS OF THE URETHKA OF THE OX AT 

 DIFFEKENT POINTS. 



i, Irdrapelmo portion ; 1, Wilson's muscle ; 2, 

 Erectile tissue ; 3, Urethral canal ; 4, Prostate 

 gland. — E, The middle of the penis ; 1, Fibrous 

 cord of the corpus cavernosura ; 2, Urethral 

 canal ; 3, Its erectile tissue ; 4, Envelope of 

 the corpus cavernosum. — c. At the crura of the 

 penis ; 1, 1, Cmra of the corpus cavernosum ; 

 2, Urethral canal ; 3, Its erectile tissue ; 

 4, Accelerator urina; ; 5, Ischio-cavernosus 

 muscle. 



