NUCLEOPLASMIC RELATIONS IN ARCELLA 55 



in diameter from 73 /x to 163 ix. No differences other than the 

 large diameter of the shell and of the mouth were observed be- 

 tween these large multinucleates and the smaller specimens al- 

 ready described. Penard ('02) mentions the discovery of a sim- 

 ilar difference between the multinucleate specimens he collected 

 in Switzerland and characterizes the larger group as '*tres 

 grande, a bouche tres largement ouverte, et tou jours pourvue 

 de noyaux en nombre considerable" (p. 410). Apparently no 

 Arcellas with more than two or three nuclei have hitherto been 

 reported from America. 



Measurements were made of the diameter of the shell and 

 diameter of the mouth of a sufficient number of specimens be- 



87(7) 



28f7) 



\27(7) 

 25(6)' _^^-Z4(7) -24(7) 



26(7) -25(7) 84(7) 24(7) 23(7) 



^24(7) 



Fig. 38 Arcella polypora. Family ap. 34. Pedigree showing two branch lines 

 containing members with seven nuclei each. The members of the upper branch 

 are larger than those of the lower bi-anch. 



longing to the groups with the large and small mouth openings 

 to give satisfactory means. The data obtained are given in 

 tables 22, 23, 24, 25, and 26. These data show that in every case 

 the correlation between diameter of shell and diameter of mouth 

 is high. The mean diameters and percentage of the diameter of 

 the shell occupied by the mouth are given in table 22. In tables 

 22 and 26 are also presented measurements of the diameter of 

 the shell and of the mouth of sixty large specimens collected from 

 vegetation in the Wallkill River near Bloomington, New York, 

 on September 4, 1918. The nuclear condition of these speci- 

 mens could not be determined on account of the dense color of 

 the shells, and they may have belonged to the binucleate species 



