156 ETHEL BROWNE HARVEY. 



PLATE I. 



The drawings were all made with a camera lucida of living eggs under a Zeiss 

 DD lens, ocular 2. 



FIG. i. Egg of Echinus immediately after fertilization. 



FIG. 2. Same subjected to H for 20 min. 



FIG. 3. Same after two hours in H. 



FIG. 4. Usual appearance of egg after 40-60 min. in H, showing irregular 

 outline and crinkling. 



FIG. 5. Same after 1-3 hours in H. 



FIG. 6. Same 50 min. after readmission of air. 



FIG. 7. Egg of Echinus subjected to H at metaphase for 35 hrs. 



FIG. 8. Same egg 45 min. after air is readmitted. 



FIG. 9. Same egg 25 min. later. 



FIG. 10. Same 5 min. later. 



FIG. ii. Same 5 min. later. 



FIG. 12. Same 30 min. later. 



FIG. 13. Same 10 min. later. 



FIG. 14. Same 5 min. later. 



FIG. 15. Same 15 min. later showing fusion of cells. 



