EXCRETORY ORGANS. 



593 



The Miillerian duct, finally reaches the cloaca though it does not 



y 



r 



Fig. 405. Section of the Wolffian body developing pronephros and 

 GENITAL GLAND OF THE FOURTH DAY. (After Waldejer.) Magnified 160 times. 

 m. mesentery; L. somatopleure ; a', portion of the germinal epithelium from which 



the involution {z) to form the pronephros (anterior part of Miillerian duct) takes place; 



a. thickened portion of the germinal epithelium in which the primitive germinal cells 



C and are lying; E. modified mesoblast which will form the stroma of the ovary: 



WK. Wolffian body; y. Wolffian duct. 



in the female for a long time open into it, and in the male never 

 does so. 



Fig. 406. Two sections shewing the junction of the terminal solid portion 

 OF the Mullerian duct with the Wolffian duct. (After Balfour and Sedgwick.) 

 In A the terminal portion of the duct is quite distinct; in B it has united with the 

 walls of the Wolffian duct. 



md. Mullerian duct ; Wi\. Wolffian duct. 



li. E. II. 



38 



