Effects of Hypertonic Sea Water. 



Fig. 171. Exp. 823: 3 per cent. NaCl, 16 hrs., normal 8 hrs. Egg nucleus very small and clear with 

 chromosomes persistent within vesicle and egg centrosome outside vesicle; the sperm nucleus is enormous 

 and contains much chromatic sap. 



Fig. 172. Exp. 823: Similar to the preceding. 



Fig. 173. Exp. 837: 1 per cent. KC1, 9 hrs., normal 35 hrs. Development has been stopped but the 

 egg is not dead; the germ nuclei are very large and achromatic; small achromatic spherules lie in the cyto- 

 plasm. 



Fig. 174. Exp. 822: 2 per cent. NaCl, 16 hrs., normal 8 hrs. Achromatin in large aud small vesicles 

 in the cytoplasm; germ nuclei normal. 



Fig. 175. Exp. 822: The germ nuclei are broken up into many separate vesicles, each with a chromatic 

 nucleolus. 



Fig. 176. Exp. 823: Two-cell stage from same experiment as figs. 171, 172; nuclei very large and 

 achromatic. 



Fig. 177. Exp. 822: Side view of egg in 2-cell stage, each cell containing a large sphere (S) and one 

 or more chromatic and two or three achromatic nuclear vesicles. 



Fig. 178, 179. Exp. 810: 3 per cent. NaCl, 15 hrs.: Side views of egg in 2-cell stage showing the 

 chromatin massed within the nuclear vesicle; the latter are elongated along the line of the former spindle 

 axis. 



Figs. 180-182. Same experiment as preceding; 4-cell stages from animal pole. 



Fig. 180. In one half of egg the remains of the 2d cleavage spindle are still visible and the chromatin 

 has formed no nuclear vesicle; in the other half the nuclear vesicles are elongated along the line of the spindle 

 axis, the chromatin being massed at the ends of the vesicle nearest the spheres. 



Fig. 181. Nuclear vesicles elongated along the spindle axis are present in three of the cells, and in 

 each the chromatin is massed at the end of the vesicle nearest the sphere; in the fourth cell no nuclear vesicle 

 is present, but traces of spindle fibres may be seen. 



Fig. 182. In all four cells the nuclear vesicles are rounded and the chromatin is massed near the center 

 of each vesicle. 



