PLATE LV. 



Effects of Hypertonic Sea Water, 

 All eggs shown on this plate are from Exp. 804, and were subjected to 1 per cent. NaCl in se 



for 4 hrs. 



Figs. 159-163. The sperm nucleus lies in a small area of cytoplasm near the lower pole; 1 

 nucleus lies in a larger area of cytoplasm at the animal pole ; various stages in the formation of the egg 



shown. 



Fig. 164. Two spindles, probably those of e{ 

 Figs. 165, 166. Tetrasters, probably formed 



and sperm, are joined 



Fig. 167. 

 Fig. 168. 



those of the egg and the sperm, joined 



separate 



Figs. 169, 170. Tetrasters in different phases of the separation of the chromosomes 



