(16) 



average spine number of line 41, shown in Table I and Fig- 

 ure 5. Shell size and form are almost identical, as is 

 also fission rate. The size and form of the mouth show 

 slight differences. To anticipate the conclusions of this 

 paper, it seems not improbable that lines 9 and 4i ctre to 

 be derived ultimately from a common ancestor. 



It is to be noted, in connection with Table I, that 

 the characters of size, spine number and fission rate show 

 large differences between diverse clones, wtiile the dif- 

 ferences in form of shell and moutn are small. 



When one recalls that the original ancestors of these 

 lines were isolated at the same time and from the same 

 place, and that the individuals of the different clones 

 were cultivated at the same time, under the same conditions; 

 the slides containing them intermingled in the same moist 

 chambers, it seems unnecessary to adduce any further evi- 

 dence to prove that diverse strains, differing in all the 

 characters studied, do exist in Gentropyxis, 



Ancestral correlations within a populacion. In 

 order to have a basis for comparison for the coefficients 

 of correlation showing the inheritance of diversities 

 within the single clones, coefficients of correlation were 

 computed to show the degree of such inheritance w/itnin the 

 population . in Table II are given the parental and grand- 

 parental coefficients of correlation for all the characters 

 studied. In this table two points stand out clearly. 



First, the correlation is very high for shell size and 

 high fur spine number ana mouth size, but low for the two 



