346 KING. 



EXPLANATION OF PLATE XXIX. 



Fig. 17. Vertical section through the black pole of an ovarian egg, showing 

 the migration of the nuclear debris towards the upper pole after the breaking 

 down of the nuclear membrane. Zeiss D., Oc. 4. 



Fig. 18. A high magnification of the region of the line of radiation at the 

 stage of Fig. 17. The radiation has reached its greatest extent, and the coarse 

 granules found both above and below the line of radiation at an earlier period 

 have entirely disappeared. Zeiss apoc. 2 mm., Oc. 4. 



Fig. 19. Vertical section through an egg at a later stage than that of Fig. 17. 

 The nuclear debris has taken a position directly under the black pole. Zeiss D., 

 Oc. 4. 



Fig. 20. A somewhat oblique section through an egg in the stage succeeding 

 that of Fig. 18. The radiation is decreasing and the line of radiation has short- 

 ened considerably. First appearance in the radiation of rounded granules stain- 

 ing like chromatin. Zeiss apoc. 2 mm., Oc. 4. 



Fig. 21. A later stage than that of Fig. 20. The granular masses seen in 

 Fig. 20 have increased in size and number and take a much deeper stain. Zeiss 

 apoc. 2 mm., Oc. 4. 



Fig. 22. Next section in the same egg as Fig. 21, showing the rest of the 

 granular substance in the radiation. Zeiss apoc. 2mm., Oc. 4. 



Fig. 23. Masses of granular substance near the first polar spindle. From 

 the same egg as Figs. 25-27. Zeiss apoc. 2 mm., Oc. 4. 



Fig. 24. The twelve chromatin rings vdth accompanying asters, found in the 

 nuclear substance at the stage of Fig. 19. Zeiss apoc. 2 mm., Oc. 8. 



Fig. 25. A somewhat oblique section of the first polar spindle before its 

 migration to the periphery of the egg, showing the longitudinal division of the 

 chromatin rings and a distinct aster at one pole. Zeiss apoc. 2 mm., Oc. 4. 



Fig. 26. Next section in the same egg as the preceding. Zeiss apoc. 2 mm., 

 Oc. 4. 



Fig. 27. Next section to the preceding. Zeiss apoc. 2 mm., Oc. 4. 



Fig. 28. The first polar spindle migrating towards the periphery, with its 

 longitudinal axis parallel to the upper surface of the egg. The asters at the spin- 

 dle poles have entirely disappeared, and the double chromatin rings have separated 

 into four parts. Zeiss apoc. 2 mm., Oc. 4. 



