CHANGES IN THE OVARY 



117 



together in the form of a lump, or dark mass, heaped up at one side 

 of the nuclear region, (c) Pachytenic stage. The nuclear filaments 

 again become unwound, and spread themselves out over the whole 

 nuclear region; they are, however, considerably coarser than in the 

 earlier stages, (d) Diplotenic stage. The chroinatin strands split 



Pachytenic stage. 

 FIG. 31. Developing ova from ovary one day after birth. (After Lane-Clay pon.) 



along their whole length, and the two halves of each strand at first 

 lie in pairs near to one another, (e) Dictyate stage. The split 

 strands pass away from one another, and the chromatin generally 



Diplotenic nucleus three days 

 after birth. 



Dictyate nucleus seven days 

 after birth. 



FIG. 32. Developing ova. (After Lane-Claypon.) 



becomes distributed once more throughout the nuclear region in the 

 form of a reticulum. 



The nucleus or germinal vesicle of the primordial ovum thus 

 produced then enters upon a long period of rest, the changes 

 involved in oogenesis having been completed. 1 



1 For an account of the minute structure of the Mammalian egg, together 

 with a resume of the literature, see van der Stricht, " La Structure de 1'CEuf 

 des Mammiferes," Part I., Arch, de Biol., vol. xxi., 1904 ; Part II., Bull, de 

 VAcad. Royale de Me'decine de Belgique, Bruxelles, 1905 ; Part III., Bruxelles, 



