178 H. H. NEWMAN 



viduals in some or all of their regions resemble one parent closely 

 and others resemble the other parent. This probably means that 

 the personality of each of the quadruplets was not determined 

 at the time of fertilization but that there is a struggle from the 

 beginning of life until all growth processes are at an end between 

 the two opposed parental tendencies, and whether for any region 

 one or other parental tendency predominates depends on certain 

 internal or external factors incident to growth. 



3. Probably no other material is so well adapted for the study 

 of the inheritance of meristic variates as are the scute complexes of 

 the armadillo armor. No detailed study of the inheritance of such 

 intricate* and complex groups of characters has ever been at- 

 tempted. For the most part workers in the field of genetics have 

 chosen for study rather simple substantive characters because 

 they give simpler and more readily analyzable results. Of the 

 comparatively small amount of genetic work that has been done 

 with meristic variates as a basis most of it has had to do with 

 dimensional variates, in spite of the fact that fluctuations in 

 dimensions are well known to be to a large extent influenced by 

 nutritive factors and are little if at all matters of inheritance. 

 The present material is such that the definitive condition of the 

 scute aggregates is reached in the uterus long before birth and is 

 uninfluenced by the only variable external condition that seems 

 to be present, namely, nutrition. The justification for this state- 

 ment is contained in the observation that differences of size, 

 weight and stage of development (which are unquestionably the 

 obvious results of inequalities of nutrition) in no way affect the 

 degrees, of resemblance existing between the members of sets of 

 quadruplets. There are not a few cases in which there are marked 

 discrepancies between the members of a single set with respect 

 to size, and so forth, and no corresponding difference in scute 

 counts. There is one case, for example, in which one pair of fetuses 

 appears to be fully a month further along in development, than 

 the other pair; yet all four are strikingly alike in all characters 

 having to do with scute numbers and arrangement. Other cases 

 occur in which one or three retarded fetuses are in the same cho- 



