PLATE LVI. 



Effects of Hypertonic Sea Water. 



5: 3 per cent. NaCl, 16 hrs., normal 8 hrs. Egg nucleus very small ai 

 within vesicle and egg centrosome outside vesicle: the sperm nucleus 



with 



and contains much chromatic 



Exp 



837: 1 oer cent. KC1 



Development has been stopped but the 



dead: the germ nuclei are very large and achromatic; small achromatic spherules lie in the cyt 



plasm. 



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



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 



chromatic and 



showing 



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



axis 



180-182. Same experiment 



Fig. 180. In 



has formed 



chromatin being massed 



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. 



