PLATE 5 
EXPLANATION OF FIGURES 
15 Seventy-seven minutes after insemination. The two nuclei to the right 
above are parts of the egg nucleus not yet fused together. The sperm nucleus to 
the left below. The aster is the larger sperm aster; the smaller one could not be 
found. Drawn at stage level with Zeiss 2mm. apochromat objective and compen- 
sating ocular no. 6. , 
16aand166 Twosuccessive sections of the germ nuclei, seventy-seven minutes 
after insemination. There is but a single aster derived from the larger sperm 
aster. Note the black granules in the neighborhood of the germ nuclei and aster. 
Drawn at stage level with Zeiss 2 mm. apochromat objective and compensating 
ocular no. 6. 
17 Origin of the cleavage centers. The partition between the germ nuclei 
has disappeared. The larger aster is derived from the larger sperm aster. Drawn 
at stage level with Zeiss 2 mm. apochromat objective and compensating ocular 
no. 6. 
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