another individual having the same formula, 

 there will be possessed by different individuals 

 among the offspring nine different genotypes, 

 but only four different phenotypes. The nine 

 genotypes may be represented by the formulae : 

 XXAABB, XXAABl, XXAaBB, XXAAbb, 

 XXaaBB, XXAaBl, XXAdbl, XXaaBl and 

 XXacib'b. The four phenotypes may in similar 

 manner be indicated by the formula: XAB f 

 XAb, XaB and Xab. As the "phenotype" 

 is the " type of the phenomenon " the type 

 of that which actually appears there must 

 always be as many distinguishable groups of 

 individuals as there are phenotypes; hence, 

 the readiness with which the word "pheno- 

 type" has been misinterpreted and applied to 

 the group of apparently equal individuals in- 

 stead of the constitution or assemblage of 

 characteristics with respect to which such a 

 group of individuals is apparently homo- 

 geneous. 



There is at present no satisfactory word 

 universally applicable to all groups of indi- 

 viduals possessing the same phenotype the 

 concept for which the word " phenotype " 

 itself has been misused. The words " spe- 

 cies " and " sub-species " used by taxonomiats 

 are applicable, at least in some cases, to groups 

 of such phenotypically equal individuals, but 

 no one would think at present of applying 

 either of these words to all the numerous 

 slightly differentiated groups which the genet- 

 icist is now able to distinguish and with which 

 he is obliged to work. A short and appro- 

 priate word for all such groups of individuals, 

 of whatever degree of differentiation, is greatly 

 needed. 



In my discussion of " clone " as a suitable 

 name for any group of plants or animals 

 which has been formed from a single original 

 individual by purely vegetative methods of 

 reproduction, I suggested the restriction of 

 the term to groups of genotypically identical 



