NUCLEOPLASMIC RELATIONS IN ARCELLA 



51 



and in family 16 nineteen specimens with 7 nuclei had a mean 

 diameter of 26.58 units. The distribution of diameters in these 

 two families was as follows: 



2. Differences between family ap. 5 and faynilies ap. 38, ap. 39, 

 ap. 69 and ap. 34- All of the small families were eliminated 

 early in the course of the work, in order that more attention could 

 be directed to family ap. 5; but on June 19th a new set of wild 

 specimens were isolated from the same material from which the 

 others were obtained and eight new families were reared. Five 

 of these were stopped after a short period, the other three were 

 carried along for a few days, and finally only one familj^ was kept 

 for further work. The two smaller families were labeled ap. 

 38 and ap. 39. 



a. Families ap. 38, ap. 39, and ap. 69. Of the thirty-eight 

 specimens in family ap. 38, thirty-one possessed 8 nuclei each, one 

 had 7, and the other six had 6. There were twenty-six speci- 

 mens in f amity ap. 39, all with 7 nuclei except fovir which pos- 

 sessed 6 each. The distribution of diameters of the 8-nucleated 

 specimens in family ap. 38 and the 7-nucleated specimens in 

 family ap. 39 is as follows: 



Specimens of family ap. 38 with 8 nuclei. 

 Specimens of family ap. 39 with 7 nuclei. 



There is a striking difference between the mean diameters of 

 these families and the mean diameter of family ap. 5 when con- 

 sidered from the standpoint of nuclear number. In family ap. 5 

 specimens with 7 nuclei had a mean diameter of 30.22 units as 

 contrasted with 25.91 in family ap. 39. 



