NUCLEOPLASMIC RELATIONS IN ARCELLA 



75 



46). These drawings were then measured; the results are pre- 

 sented in table 33. Although the specimens in line 58edb. are 

 very much larger than those in line 58ed., the mean diameter 

 of the chromatin mass within their nuclei is almost exactly the 

 same, being 8.73 n in the former and 8.44 ix in the latter. These 

 data suggest that the large specimens were unable to exist be- 

 cause of the small quantity of chromatin they possessed in com- 

 parison with the large amount of cytoplasm. Why the chroma- 

 tin did not increase in amount to keep pace with the enlarge- 

 ment of the cytoplasmic body is a question that cannot now be 

 answered. 



O o o o 



A 



o o o o 



B 



Fig. 46 Arcella dentata. Outlines of the chromatin masses within the nuclei 

 of living specimens. A = one chromatin mass from each of four specimens from 

 the small parent line, ed. B = one chromatin mass from each of four specimens 

 from the large branch line, edb. X 630. 



TABLE 33 



Arcella dentata. Table showing the relation between the diameter of the shell and 

 the number of spines, and the diameter of the chromatin mass in four specimens 

 each in lines 58 edb. and 58 edc. 



