of the Genera of the Aranee. 405 
As a matter of fact, the adoption of the method of “ elimina- 
tion”? is simply the logical application of the very rule which 
Dr. Dahl himself quotes as follows :—“ The first publication 
wn which a genus is subdivided, whether justifiably or unjusti- 
fiably, whether in a conscious or an unconscious manner, must, 
where no typical form was named, decide what portion of the 
original genus ts to retain the or iginal name.’ 
If the first publication leaves more than one species in the 
genus, then the next publication which again subdivides the 
residue will decide what portion of the original genus is to 
retain the original name, and so on until one species only is 
left, and this remains as the type. And if not, why not ? 
And if so, this is just simply the process of “ elimination ” 
or “‘ exhaustion.” 
If the International Rules allow an author to limit a genus 
to ten species, on what logical grounds will they forbid him 
from limiting it to ONE species ? And if an author definitely 
elects (or cites) a single species as the type, he is simply, 
“justifiably or unjustifiably, consciously or unconsciously,” 
deciding what portion of the original genus (a single species 
in this case) shall retain the original name. The process is 
not precisely similar to that of elimination, but for all practical 
purposes it is the same. 
Elimination pure and simple. 
Now elimination pure and simple proves in its practical 
application almost invariably to land us in an absurdity. In 
this way: the species which authors withdraw are usually 
those that are best known, with characters salient and well 
described, leaving in those less well known—with this result, 
that the last species left in is one which is not known, is 
badly described, and is never likely to be identified with any 
certainty ; and this miserable phantom is left us as the type of 
the genus, In its simplest and purest form the process often 
ends in a futility. 
But by recognizing the definite selection or citation of a 
type species systematists may overcome this difficulty, and 
by a process not inconsistent with the Rules of International 
Nomenclature. Because, it will be noted, most authors in 
citing a type species have selected as typical those that are 
well known to them, and hence the genus will be represented 
by a species whose characters can be always ascertained; so 
that for ‘‘ practical purposes,” and we are now concerned with 
none other, the process or method which most of all serves in 
bringing about a reasonable and practical result is one of 
