INHERITANCE OF VARIATES IN THE ARMADILLO 157 



than the general polyembryonic one. This goes to emphasize 

 further the vaUdity of the law that degrees of resemblance are 

 in direct proportion to degrees of blood relationship. 



Knowing the mode of origin of the quadruplets as we do the 

 real problem, it seems to me, is to explain not so much why the 

 individuals of a set are so similar but why they are not exactly alike. 

 How are the differences effected and what are the developmental 

 factors producing divergent characters among the individuals de- 

 rived from a single fertilized egg? Are the differences simply the 

 product of the inequalities in the environic factors incident to 

 growth or is there an unequal distribution of inheritance mate- 

 rials? These are questions that will inevitably recur as we pro- 

 ceed with the presentation of data and that can not be discussed 

 to advantage until all the available facts are systematically 

 arrayed before the reader. 



3. CORRELATIONS BETWEEN MOTHERS AND OFFSPRING 



This phase of heredity was neglected in the previous paper 

 owing to lack of data concerning the mothers. None of the shells 

 of the mothers were preserved and in only a few cases were 

 scutes of the banded region counted before the carcasses were 

 destroyed. This oversight was the result of a failure, until too late, 

 to appreciate the opportunities afforded by the material for the 

 study of certain unique phases of heredity. Our attention was 

 focused on the problem of polyembryony to the exclusion of its 

 consequences and of the bearings of the latter on the broader prob- 

 lems of genetics. The present collection of material, however, 

 makes good the earlier deficiency in that the complete armor of 

 each mother is permanently preserved and a detailed comparison 

 can be made between parent and offspring. 



Male and female sets are dealt with separately and comparisons 

 are thus made possible between the indices of heredity in the two 

 sexes. In some few cases the shells of the mother were too badly 

 scarred or otherwise damaged to afford an accurate scute count 

 and in such cases it was necessary to exclude both mother and off- 

 spring from the tables. In other cases the fetuses were either too 



