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 sea water 

 for 4 hrs. 



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

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

 are shown. 



Fia. 164. Two spindles, probably those of egg and sperm, are joined at one pole. 



Figs. 165, 166. Tetrasters, probably formed from the egg and the sperm spindles. 



Fig. 167. Two spindles, probably those of the egg and the sperm, joined at one pole. 



Fig. 168. Two spindles, probably those of the egg and sperm, quite separate. 



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



