NUCLEOPLASMIC RELATIONS IN ARCELLA 



73 



microns. The following data selected from this table show that 

 in members of the two families with shells nearly alike in diame- 

 ter the nuclear number is different, but the volume of the chro- 

 matin is very nearly the same. 



The differences in chromatin volume between the pairs of groups 

 are not greater than would be expected as a result of slight 

 errors in the measurements. In figure 45, A, are shown out- 

 lines of the eight chromatin masses from a typical specimen from 

 family ap. 34, and in figure 45, B, outlines of the five chromatin 

 masses from a typical specimen of the same size from family ap. 5. 



oooooooo 



A 



B 



Fig. 45 Arcella polypora. Outlines of the chromatin masses within the nu- 

 clei of living specimens. A = eight chromatin masses from a typical specimen 

 from family ap. 34. B = five chromatin masses from a typical specimen of the 

 same size from family ap. 5. C = five chromatin masses from a very large speci- 

 men, ap. 74. X 900. 



