THE GENITAL GLANDS AND DUCTS— UTERUS AND VAGINA 219 



collecting tubules which forms a rudimentary structure, the epoophoron (Fig. 

 238 B). In its cords lumina appear, the epithelial cells become ciliated, and 

 smooth muscle tissue is developed corresponding to that of the epididymis. 

 The caudal group of mesonephric tubules constitute the paroophoron. Usually 

 the greater part of the male genital ducts atrophy in the female, the process be- 

 ginning at 30 mm. Thus the tubules of the epoophoron are left without an out- 

 let. Portions of the mesonephric ducts persist as Gartner's canals. 



These may extend as vestigial structures from the epoophoron to the lateral walls of the 

 vagina, passing through the broad ligament and the wall of the uterus. They open into the 

 vagina close to the free border of the hymen (R. Meyer). The canals are rarely present 

 throughout their entire length and are absent in two-thirds to three-quarters of the cases 

 examined. It is an interesting fact that in male and female embryos the ducts of the opposite 

 sex begin to degenerate at the same stage, 30 mm. 



The Uterine Tubes, Uterus and Vagina. — The Miillerian, or female ducts, 

 after taking their origin as described on p. 210, grow caudally, following the 

 course of the mesonephric ducts (Fig. 224). At first lateral in position, the 

 Miillerian ducts cross the mesonephric ducts and enter the genital cord median 

 to them (Fig. 238 A). In embryos of 20 to 30 mm. their caudal ends are dorsal 

 to the urogenital sinus, extending as far as the Miillerian tubercle, a projection 

 into the median dorsal wall of the vesico-urethral anlage formed by the earlier 

 entrance of the mesonephric ducts (Fig. 219). This tubercle marks also the posi- 

 tion of the future hymen. In fetuses of 70 mm. (C H) the Miillerian ducts 

 break through the wall of the urethra and open into its cavity. Before this 

 takes place the caudal ends of the Miillerian ducts, which are pressed close 

 together between the mesonephric ducts in the genital cord, fuse, and in both 

 male and female embryos of 20 to 30 mm. give rise to the unpaired anlage of the 

 uterus and vagina (Figs. 219 and 231 A). The paired cranial portions of the 

 Miillerian ducts become the uterine tubes. During development the ostial ends 

 of the uterine tubes undergo a true descensus from the third thoracic to the fourth 

 lumbar vertebra. 



The utero-vaginal anlage of the male remains rudimentary. The uterine 

 portion of the anlage degenerates with the paired portions of the Miillerian 

 ducts. The vaginal portion remains as the vagina masculina (prostatic utricle), 

 and the extreme cranial end of each Miillerian duct persists as the appendix 

 testis. 



As pointed out by Tourneaux and especially by Felix, the term "uterus masculinus" 

 as applied to the remains of the utero-vaginal anlage is a misnomer, for the vaginal portion 

 of the anlage persists and its uterine portion degenerates. 



