THE ORGANS OF THE MIDDLE GERM-LAYER. 401 



Fig. 230. 



Fig. 2S1. 





Tigs. 230 and 231. Six stages in the development of the external sexual organs i 



the female, after the ECKER-ZIEGLEK wax models. 

 Fig. 230 A andB. 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 JV/ and 31* 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 (2J and 4J 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, perinamm ; a, anus ; ug, entrance 



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



lit, scrotum ; d & r, raphe perinei and scroti ; ysch, labia majora ; ksch, labia minora. 



COLLll 01-" ^WO 



/. I, i: I- I I : S- . li . ^ , A.L. 



