Eugene Howard Harper 369 



EXPLANATION OF DIAGRAMS 1-6. 



Diagram 1. Diagram showing number and relative position of accessory 

 nuclei in the egg. The male and female pronuclei are in the center, lying in 

 contact. Two sperm nuclei nearer than the rest. Same egg as in Fig. 11. 



xio. 



Diagram 2. Pronuclei in closer contact. Same egg as shown in Fig. 12. 

 Owing to the incompleteness of the series the number of sperm nuclei is too 

 small. X 10. 



Diagram 3. Stage of segmentation nucleus. Accessory nuclei are mostly in 

 pairs, indicating previous division. Same egg as Fig. 13. X 10. 



Diagram 4. Stage of first cleavage spindle. Same egg as Fig. 14. x 10. 



Diagram 5. First furrow is beginning to appear at surface (f). The two 

 cleavage nuclei equidistant. Same egg as in Fig. 15. X 10. 



Diagram 6. Beginning of second division. The accessory nuclei appear 

 nearer the center of the disc than in the previous stage. X 10- 



