THE ORGANS OF THE MIDDLE GERM-LAYER. 



401 



Fig. 230. 



\ 



d&r 



Fig. 231. 



W* \ 



Figs. 230 and 231. Six stages in the development of the external sexual organs in the male and 



the female, after the ECKER-ZIEGLER wax models. 

 Fig. 230 A and B. Two stages in which a difference of the sexes is not yet to be recognised, 



B from an embryo S weeks old. 

 Fig. 231. The two stages 3/and M* exhibit the metamorphosis of the original fundament in 



the male in embryos 2J and 3 months old respectively. The stages W and IF* present the 



metamorphosis in the female (2 and 4J months). 

 The same designations are used for all of the figures. 

 he, Posterior paired extremity ; do, cloaca ; gh, genital eminence ; (if, genital fold ; gr, genital 



groove ; gw, genital ridges ; gp, glans penis ; cl, clitoris ; d, perinaeum ; , anus ; v.y, entrance 



to sinus urogenitalis or vestibulum vaginae ; vv, vestibulum vaginas ; rh, foreskin (prepuce) ; 



Its, scrotum ; d <& r, raphe perinei and scroti ; gsch, Jabia ruajora ; ksch, labia niinora. 



26 



