THE GENITAL GLANDS AND DUCTS UTERUS 



227 



the caudal ends of the Muellerian ducts, which are pressed close together between 

 the mesonephric ducts in the genital cord, fuse, and in both male and female em- 

 bryos of 20 to 30 mm. give rise to the unpaired anlage of the uterus and vagina 

 (Fig. 224 A). The utero- vaginal anlage of the male remains rudimentary. The 

 uterine portion of the anlage degenerates with the paired portions of the Muel- 

 lerian ducts. The vaginal portion remains as the vagina masculina, and the 

 extreme cranial end of each Muellerian duct persists as the appendix testis. 



As pointed out 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. 



Uterus and Vagina. Since the Muellerian ducts develop in the urogenital 

 folds, they make two bends in their course corresponding to those of the folds 



Cerw'y. 

 Uteri 



Uterine tube 



Futidus of Uterus 



RauncL 

 L i a ament 



HorizonfaL portion 

 of iferi ne tube 



Mesenchyme. 



FIG. 224. Diagrams showing the development of the uterus and vagina (modified after Felix). 



(Fig. 224 A). Each consists of a cranial longitudinal portion, a middle transverse 

 portion and a caudal longitudinal portion, which is fused with its fellow to form 

 the utero-vaginal anlage. At the angle between the cranial and middle portions 

 is attached the inguinal j old, the future round ligament of the uterus (Figs. 225 

 and 226). The mesenchyma condenses about the utero-vaginal anlage and the 

 middle transverse portion of the Muellerian ducts, forming a thick, sharply de- 

 fined layer, from which is differentiated the muscle and connective tissue of the 

 uterus and vagina (Fig. 224 B). As development proceeds the cranial wall be- 

 tween the transverse portions of the Muellerian ducts bulges outward so that its 

 original cranial concavity becomes convex (Fig. 224 B). The middle transverse 

 portions of the ducts are thus taken up into the wall of the uterus forming its 



