MARcH 29, 1901.] 
most recent writers a type is definitely as- 
signed by the author of the genus. In 
modern rules of nomenclature the defini- 
tion of a genus may be altered or even re- 
versed, but the generic name must adhere 
to the original type. 
The most serious difficulty in connection 
with the matter of nomenclature lies in 
the reduction of the ancient conception of 
the genus to the terms of the modern one. 
It lies in-the assignment of a type species 
to a group in which the original author had 
no conception of the need of such a species. 
In the subdivision and fixation of the 
ancient genera, various methods have been 
followed, with varying results. In other 
words, these methods have lacked the one 
important element of inevitableness. A 
rule of nomenclature has little value unless 
it lies in the nature of things. If it is 
artificial, it will be discarded. 
In general, three methods have been fol- 
lowed in fixing the types of the early com- 
posite genera : 
1. To follow the arrangement of the 
author who first subdivides the genus sub- 
sequent to the work of the original author. 
In this many difficulties have been found 
in practise. The first restriction is often 
in obscure publications. It is often ob- 
scurely done. In other words, a genus is 
often subdivided in such a way as to leave 
no clear idea as to what the author would 
leave in the original group. Sometimes he 
leaves nothing at all, as in the case of the 
Linnean genus, Sparus, for which no place 
was left after its subdivision. Asa matter 
of fact, this system leaves the proper ap- 
plication of many generic names in doubt, 
and necessitates a profitless investigation 
of the opinions of early authors who wished 
to improve Linnean nomenclature, but 
who worked on too small a scale to accom- 
plish much. 
A second system derived from this is the 
method of elimination. The genus of the 
SCIENCE. 
499 
eighteenth century corresponds roughly to 
the family of the nineteenth. The family 
may contain several genera. These may 
be withdrawn from the original genus in 
chronological order, and the old name left 
with the final residue. But this residue 
will generally consist of foreign species or 
species unidentified or unidentifiable. To 
meet this difficulty the method of elimina- 
tion in birds has been applied to European 
species only, that generic names based pri- 
marily on European forms may not be 
forced out of the European fauna. ‘To 
make the system workable a variety of 
other minor rules must be invented, as a 
little change in the point of view as to some 
obscure author will make an entire change 
in the final result. The final result is the 
only matter of interest. - 
Fhe ornithologists have found this 
scheme workable and it is incorporated in 
the rules of the American Ornithologists’ 
Union. But even here it has not yielded 
stability of nomenclature, as several ge- 
neric names (as of owls, loons) have been 
more than once altered in obedience to its 
dictates. But in American ornithology 
any rule has the great advantage of the 
imposition of authority. The ornitholo- 
gists of America agree to stand by their 
committees, and any decision these may 
make is final for them and their associates, 
that is for most ornithological work in 
America for the present generation. 
Other branches of science have no such 
authority behind their verdicts, and without 
it the determination of generic types by 
elimination is a failure. Often two men 
working independently cannot reach by 
the same rules an identical result. It is 
not always easy for the same man to reach 
the same result twice. 
Let us take a concrete problem. The 
genus Clupanodon of Lacépéde (1802) con- 
taining those herrings which have no teeth 
includes several modern genera. 
