992 GENERATIVE APPARATUS. 



enlarged appendix ; between the two layers forming this fold is found a thin 

 muscle, altogetlier like the male cremaster before the descent of the testicle into 

 the scrotum. This may be looked upon as the analogue of the round ligament of 

 Woman. 



The uterus is also fixed in its situation by its continuity with the vagina. 



Interior. — The inner surface of this organ shows mucous folds, which exist 

 even in the foetus ; they are arranged in a longitudinal series, and are not 

 effacable by distension ; though they disappear during gestation, consequent on 

 the enlargement that takes place in the uterine cavity. 



This cavity has three compartments : the cavity of the body, and those of the 

 cornua. The latter are pierced, at their extremity, by the uterine orifice of the 

 Fallopian tube ; while the former communicates with the vagina by a narrow 

 canal that passes through the posterior constriction of the uterus (cervix), 

 and which is, in Human anatomy, named the cavity of the cervix (os uteri, os 

 externum, os tricce). In all the domesticated animals, except the Rabbit, this 

 canal is prolonged to the bottom of the vagina, in something the same fashion 

 as a tap is into the interior of a barrel ; and in this way it always forms a very 

 marked projection in the vaginal cavity. Around this projection, the utero- 

 vaginal mucous membrane is raised in transverse folds disposed in a circular 

 manner, which give it the appearance of a radiated flower ; in Veterinary 

 anatomy, this projection of the cervix is consequently named the "expanded 

 flower "— ^(?Mr epanouie ; it is the tench's nose of the Human being. 



Structure. — The walls of the uterus are composed of three membranes — 

 an external, serous ; a middle, muscular ; and an internal, mucous ; with vessels 

 and nerves. 



The serous tunic envelops all the organ ; it is an expansion of the broad 

 ligaments, which are prolonged backwards on the posterior extremity of the 

 vagina, and are afterwards doubled in a circular fashion around that canal, to 

 pass over either the rectum, the bladder, or the lateral walls of the pelvis. 

 Between the two cornua this membrane forms a particular fraenum, which is only 

 slightly developed in Solipeds. 



The muscular layer comprises longitudinal (superficial), and circular (deep) 

 fibres, analogous to those of the small intestine. Near the insertion of the broad 

 ligaments, they give off a series of fasciculi which are prolonged between the 

 two layers of these ligaments. These are not the only smooth muscular fibres 

 met with in the ligaments, however ; for Rouget has found others throughout 

 their whole extent, but particularly in the vicinity of the ovaries.^ (Around the 

 cervix uteri, the circular fibres are most dense and numerous.) 



In the pregnant animal, the number of fibres composing this layer is much 

 more considerable than in ordinary circumstances ; this increase has for its object 

 to permit the dilatation of the uterus, without allowing its parietes to become 

 too attenuated ; they do become more or less thin, notwithstanding, according 

 to the species. It has also been remarked that, during pregnancy, the muscular 

 fibres present a manifest striation. (The elements of these fibres are short fusi- 

 form cells w;ith long oval nuclei, mixed with a large quantity of embryonic, 

 nucleated connective tissue.) 



The mucous membrane is very rich in cellular elements, and is thin, delicate, 

 and raised into folds. It ia covered by ciliated epithelium, which becomes 



* Unstriped contractile fibres are alao found, in the male, along the spermatic cord, beneath 

 tlie yisceral layer of the tunica vaginalis. 



