1% f-ttS 0T> 
W. B. 2. 
should cross refer to this one. The reason for this is that the 
Index will be used in the fut ure, not in the pas t. Consequently 
the generic name sought for would be, in nine cases out of ten,the 
name last adopted by the Union. We know very well from experience 
that in a few years former generic combinations will be forgotten 
and only the current name used. There are two or three cases, I 
believe, in which the Union has accidentally made a wrong ruling, 
which ruling may be corrected in time for the Index. Of course 
you understand that all generic names used in the text,from the 
first volume of the 'Nuttall Bulletin' down to date, will be given 
in the Index ( and that each will be followed by a cross reference 
to the modern generic name under which all page references are 
given. 
Now as to subspecies: Inasmuch as an index is an index and , 
not a c lassification, it deals with names and has nothing to do 
with matters of rank. Therefore, in our judgment, subspecies for 
index purposes should bo treated as species, exactly as in the case 
of nomenclature. In the case of subspecies and subgenera, there 
always has been, is, and always will be difference of opinion as to 
the matter of rank. The history of our own Checklist as well as 
the experience of zoologists and botanists throughout the world 
shows not only that what one man regards as a species and genus, 
another mm regards as a subspecies and subgenus; but that individual 
authors and committees change their points of view from time to time 
as to the rank of a particular form or collection of forms, so that 
while names are matters of fact conceded by common agreement to be 
fixed and stable, matters of rank are matters of opinion , cannot 
possibly be fixed,and are undergoing constant fluctuation^. 
