146 H. H. NEWMAN 



seem advisable then at the outset to acquaint the reader with 

 what the writer conceives to be the problems peculiar to the mate- 

 rial and to indicate some of the main lines of analysis employed 

 in the solution of these problems. 



The principal problems may be briefly stated as follows: 



1. In what respects are the modes of inheritance of polyem- 

 bryonic offspring different from those of the ordinary kind? Does 

 the fact that, in the case of the armadillo, four offspring come from 

 a single fertilized egg involve any unusual inheritance features 

 not present in cases where a fertilized egg produces only one 

 offspring? 



2. Since the quadruplets derived from a single fertilized egg 

 are, in consequence of their mode of origin, more closely related 

 genetically than brothers or any other blood relatives, are they 

 more closely similar than any other relatives? In other words, 

 to just what extent is the basic assumption of taxonomy, that the 

 degree of resemblance is a function of the degree of blood relation- 

 ship, borne out in the present material? 



3. In view of our knowledge that the originally single blasto- 

 dermic vesicle divides at a very early period into four distinctly 

 independent embryonic rudiments, to what extent is it possible 

 to determine what characters are predetermined before the separa- 

 tion and what are modified by individual experience during devel- 

 opment? In brief, is it possible to estimate in this apparently 

 exceptionally favorable material the relative values of predeter- 

 minative and epigenetic factors in the development of any given 

 definitive character or set of characters? 



4. In view of the fact that extremely trivial personal minutiae 

 seem to be strongly inherited in certain peculiar ways by individ- 

 uals or sets of quadruplets, what sort of conception of the charac- 

 ter of the predetermining germinal basis accords with the facts? 

 What is the nature of the predeterminers of personal minutiae? 



5. What is the mode of inheritance of meristic variates or of 

 aggregates of these? Are they inherited in the blended fashion 

 as dimensional variates appear to be, or according to the laws of 

 alternative inheritance after the manner of substantive varia- 

 tions? 



