250 OUTLINES OF EQUINE ANATOMY. 



given off by the posterior aorta, runs tlirougli tlie broad 

 ligament to the ovary, wliere it breaks up, forming, accord- 

 ing to some anatomists, a tunica vasculosa surrounding the 

 organ. It corresponds to the spermatic artery of the male, 

 than which it is much smaller. Through this ligament, 

 the vessel corresponding to the artery of the cord in the 

 male, the uterine artery takes a convoluted course down- 

 wards and backwards. It is much larger than the artery 

 of the cord, and increases very considerably in size during 

 pregnancy. The muscular coat of the uterus presents two 

 layers of fibres ; longitudinal externally, circular internally 

 (it also has oblique fibres) . These are of the unstriated order, 

 but during pregnancy become developed into fibres with faint 

 traces of striae. The mucous membrane is of a reddish colour, 

 and collected into rugae in the unimpregnated uterus. It 

 becomes highly vascular, and its epithelium much increased 

 in quantity during pregnancy ; for the blood of the foetus 

 passes to the chorion, a membrane lying in intimate con- 

 tact with the vascular part of the mucous membrane of 

 the dam, and in which the ^^rocess of aeration of the blood 

 ensues. (The excess of epithelium after parturition is 

 thrown off as the membrana decidua.) In some parts, 

 especially up against the fallopian tubes, the epithelium 

 is ciliated, serving to waft the spermatozooa upwards. 

 Around the neck of the organ the mucous glands increase 

 in complexity, and secrete a more viscid matter ; they are 

 the glandulce of Nahoth. The muscular coat in the cervix 

 uteri is very thick, thereby causing puckering of the 

 mucous membrane longitudinally in this part ; laterally 

 it comes in contact with the muscular coat of the vagina, 

 and posteriorly, covered by the mucous membrane, pro- 

 jects in a remarkable manner into the vaginal cavity "like 

 the tap of a beer barrel," thus forming the cauliflower 

 excrescence {fleur ^panouie of the French anatomists) , which 

 projects more inferiorly than superiorly. 



The vagina is the cavity placed immediately posterior 

 to the uterus extending to the vulva, from which it is 

 separated by the hymen. It is largest centrally, becoming 

 anteriorly constricted in surrounding os uteri, and running 

 to join the cervix ; posteriorly smaller in joining the vulva ; 

 superiorly it is in contact with the rectum ; inferiorly with 

 the bladder. Its anterior part is covered with peritoneum, 

 which laterallv blends with the broad ligaments of the 



