R. Peahi, and f. J. Dinüar IVM 



The rcsults ,-inil roiiclusioiis iiuu' l)i' .suiiiniai'i/.i'il ;is lollows: 



1. Botli tho (liaiiictcr of Uic slicll and u\' tJir (i|icninL( sliow a rcasonably 

 higli variability. 'l'lic IVccniciicy distributiinis f'or Ixilli cliaraclors an- uiiiniodal 

 aiul markedly .skuw. 



2. Tlie opening in the sshell is deoidedly moru variable in size tlian is tln.' 

 whole sholl, sizo in both cases bcing indicated by the rcspcctive diametcrs. 



•S. The coefficients of Variation f'or tho two dianiotcrs ((ipening aiul total sholl) 

 presont values in very fair accord with those obtained by Simpson for size eharacters 

 in Paraniacium, showing that thesc organisms are approxiniatcly e([iially variable 

 in corresponding eharacters. 



■i. There is a high degree of positive correlation (cootticient = 'S-l) between the 

 diameter of the shell and of the opening. 



5. Regression and characteristic equations for determining the mean total 

 diameter of the shell associated with a given diameter of the opening and vice 

 versa, are given. 



G. There is found tu be an extremely small degree of correlation (coefficient 

 = •()!) between the size of the shell and its colour within the size limits of the 

 series of individuals discussed. The correlation is so small as to be practically 

 insensible. 



7. There is no sensible change in the averagc size of the sliells as indicated 

 by random samples, within the period of the life of the culture studiud. This 

 period covered approximately three weeks in time. 



Biometiikii ii 43 



