PLATE 2 



EXPLANATION OF FIGURES 



14 First maturation division occurring at a point where the alveolar layer 

 has been extruded; 60 minutes after insemination. 



15 Entrance of the sperm, showing the non-staining vacuole. 



16 Tripolar spindle of the first maturation; .55 minutes after insemination. 



17 First maturation spindle, showing an abnormal distribution of the chromo- 

 somes; 60 minutes after insemination. 



18 The second maturation. The first polar body has not been extruded; 80 

 minutes after insemination. 



19 The same; two sperms are entering in one, the aster has appeared before 

 the revolution of the cone. 2 mm. X No. 0. 



20 The cleavage nucleus. The chromatin is passing out through the nuclear 

 wall; 120 minutes after insemination. 



21 Polyspermy; 70 minutes after insemination. 



22 Division of the protoplasm without a distribution of the chromatin. 2 mm. 

 apochr. X No. eyepiece. 



23 The same; the same magnification. 



24 to 30 Normally fertilized eggs radiated. 



24 Approach of the germ nuclei; 105 minutes after insemination. 



25 The nuclei have migrated to oppositie sides of the egg; 105 minutes after 

 insemination. 



126 



