1940 



HUMAN ANATOMY. 



the ejaculatory ducts, the permanent representatives of the Wolffian ducts. In the 

 female the tract produces the entire urethra, since the oririce of the sexual canals 

 opens into the uro-genital sinus. The bladder, therefore, is composite in origin, its 



Broad ligament 



FIG. 1649 



r.:.ni lei 



Symphysi; 



Clitoris- 



Glaus 

 Epithelial knob. 



Anus^^^. 

 Uro-genital sinus 



Rectum 



Spinal cord 



Xotochord 



Ureter 



Mullerian ducts 



Wolflian duct 



Reconstruction of human embryo of nine weeks (25 mm. length) ; ureter has migrated to 

 bladder, leaving Wolffian and Mullerian ducts attached to uro-genital sinus, which is com- 

 pletely separated from intestine. X 10. (Drawn from Keibel model.) 



upper part being from the allantois alone, while in the formation of the trigonal region 

 both allantois and cloaca take part. The remaining portions of the urethra in the 

 male are formed by the extension of the uro-genital sinus along the under surface of 

 the corpora cavernosa of the developing penis (page 2044). 



