CELL DIVISION IN EGGS OF CREPIDULA. 91 



Fig. 216. Exp. 846: Egg from same experiment as the preceding; the nuck at the vegetal pol 

 nmbablv derived from chromosomes which were scattered along the first cleavage spindle as in fip 



are 



Fig. 217. Exp. 822: 2 per cent. NaCl, 16 hrs., normal 8 hrs.: irregular and unequal 2d cleavage with 

 era! karyomeres of varying size in each cell. 

 Fig. 2i8. Exp. 842: 4 per cent. MgCh, 5 hrs., normal 17 hrs.; the divisions of the cell bod; at the 2d 



ppressed in the left half, but two micromeres are arising in normal manner from this half 



several accessory alters are present in this half which have served to scatter the chromosome?. The right 



half of the egg is quite normal. 



Fig. 219. Exp. 867: 8 per cent. MgCU, f hr., normal 6} hrs.; the 3d cleavage was very irregular and 

 has riven rise to a large number of karyomeres, and spheres which are in division in three quadrants of 



i. 220. Exp. 972: 2 per cent. NaCl, 16 hrs., normal 21 hrs.; second quartet formation; karyomeres 



or polyastere in each of the cells. 



Fig. 221. Exp. 814: 2 per cent. NaCl, 1 hr., normal 17 hrs.; second quartet forma 1 >n; karyomeres 



and spheres in every cell. 



Fig. 222. Kxp. 828: 1 per cent. NaCl, 2 hrs., normal 6 J hrs.; second quartet formation; karyomeres 



and polya>ters in every cell. 



Fig. 223. Exp. 972: 2 per cent. NaCl, 16 hrs., normal 24 hrs.; karyomeres (and asters) in every 

 roU- nil nuclei are vesicular and contain achromatin as well as chromatin. 



