THE AMERICAN NATURALIST [Vol. XLII 



In conclusion, I submit the following propositions: 



1. The individual is the taxonomic unit, usually un- 

 designated. 



2. Similar individuals constitute a race. 



For general taxonomic purposes races need not be 

 designated ; the conception and description of the species 

 is broad enough to include all races of which it is com- 

 posed. There will never be complete uniformity of 

 agreement as to the distinction between races and species, 

 any more than there will ever be complete agreement as 

 to the limitations of genera. It is futile in science to 

 attempt to lay down principles which interfere with indi- 

 vidual judgments. For special purposes the races may 

 be designated numerically, as, Quercus alba, race 2; 

 Oenothera biennis, race 12; Bursa Biirm-pastoris, race 17 ; 

 Draba verna, race 104. There are doubtless many in- 

 stances where the species is composed of only one race, 

 just as we have monotypic genera composed of but one 

 species. 



3. Similar races constitute a species, the species des- 

 ignated binomially. 



4. Similar species constitute a genus, the genus des- 

 ignated monomially. 



