I6O ETHEL BROWNE HARVEY. 



PLATE III. 



FIG. 30. Same 20 min. later. 



FIG. 31. Same i hr. later. 



FIG. 32. Another egg of Strongylocentrotus subjected to H at metaphase for 

 15 min., then air admitted for 3 hrs. 



FIG. 33. Same 10 min. later. 



FIG. 34. Same 30 min. later. 



FIG. 35. Same 20 min. later. 



FIG. 36. Echinus egg subjected to H for 20 min. in anaphase. 



FIG. 37. Same egg still under His min. later. 



FIG. 38. Same egg still under H 30 min. later. 



FIG. 39. Echinus egg subjected to H for 1 7 min. in anaphase. 



FIG. 40. Same egg still under H a few min. later. 



FIG. 41. Same egg still under H 30 min. later. 



FIG. 42. Echinus egg divided while subjected to H for 15 min. 



