THE ORGANS OF THE MIDDLE GEKiM-LAYER. 



Fig. 230. 



401 



Fig. 231. 



dd-r 



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 8 weeks old. 

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



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



metamorphosis in the female (2 and 4 months). 

 The same designations are used for all of the figures. 

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



groove ; gw, genital ridges ; gp, glans penis ; cl, clitoris ; d, perinaeum ; , anus ; ug, entrance 



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



hs, scrotum ; d & r, raphe perinei and scroti ; gsch, labia majora ; ksch, labia minora. 



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