ANATOMY. 45 



and thickly coated with muscular fibres. Farther forward 

 than this the vagina is composed of membrane. 



The Membrane of the Vagina. — The part of which it is 

 constituted is one of the mucous class, and one that pos- 

 sesses considerable density, extensibility, and resistance. 

 Its exterior surface is rough. Its interior is smooth, and has 

 a pale pinkish cast ; unless the mare be under the venereal 

 oestrum, and then its redness is heightened, and its secretion 

 augmented. In the ordinary state, this membrane is thrown 

 into folds, larger in breeding mares than in others, technically 

 called rugae. 



Considerably in advance of the clitoris is an opening 

 leading from the lower part of the canal, large enough to 

 admit with ease any one of the fingers : this is the orifice of 

 the meatus urinarius, or outlet of the bladder : it is guarded 

 by a doubling of the vaginal membrane, which hangs over 

 it, and serves the purpose of a valve. 



The large and conspicuous protuberance at the bottom of 

 the vagina, is the mouth of the uterus. 



The uterus, or womb, is a hollow musculo-membranous 

 organ, united to the anterior part of the vagina, and is des- 

 tined for the reception of the foetus. We distinguish the 

 uterus by the body, horns, neck, and mouth. The body is 

 the oblong or cylindrical part, growing out of the anterior 

 portion of the vagina, in the centre of which it is terminated 

 internally by the os uteri, or mouth of the womb ; it gives 

 origin, in front, to the horns. This part lies wholly within 

 the pelvis, between the bladder and rectum, and is entirely 

 covered by peritoneum. 



The cornua, or horns, rise from the body of the uterus, and 

 diverge towards the loins. Their length and size will be 

 much greater in breeding mares than in others. In figure 

 they are cylindrical ; they bend upwards in their course, and 

 terminate in round extremities, to which are loosely appended 

 the ovaries, or testicles, through the medium of the Fallopian 

 tubes. 



The cervix, or neck, of the uterus is the rugose portion 



