35 
in diagnosing forms, whereby species have been thought 
to be distinct which are really alike, owing for instance 
to a misapprehension of a minor variation either in 
colour (due merely to differing degrees of intensity), in 
size, in habitat (e. g. lake- and marine perch), or in 
spawning-time, etc., he lays special stress on the need 
for accuracy and discrimination; such slight variations 
do not give rise to the establishing of new Species, but 
only to "Varieties". 
Just as ARTEDI, after defining what was to be under- 
stood by genus, subjected genus-names to a severe scru- 
tiny, so now, when he has discussed species in general, 
he goes on to examine critically the names in use for 
them. "A species-name", he says, u is the epithet, con- 
sisting of some few words, which is appended to the 
genus-name, in order to distinguish one fish species from 
the others in the same genus". These epithets must be 
effective for the function they are thus required to per- 
form; if they only state the more or less general oc- 
currence of the species, its assumed sequence in the 
genus, home, mode of occurrence, size, varying colour 
or markings, etc., they are, as being of no use to the 
reader, spurious and repudiable. Genuine species-names, 
on the other hand, are those which serve to mark off 
at a glance, or with a minimum of effort, one species 
from the others in the same genus. They must, in 
other words, state such genuine species-characters as 
have been mentioned in the foregoing. 
In having solved the question of genus-names so 
excellently, by enunciating such clear and definite rules 
for their use, ARTEDI was on the very threshold of a com- 
plete solution of the nomenclature problem; there would 
seem to have been but one simple step for him to take, 
to arrive at the law of binomenclature; however, in 
treating species-names he drifted away from the right 
track, owing to the exacting demands he made upon 
them. Genus-designations, or generic names, he trans- 
formed into real names, but in dealing with species 
names he confused the two ideas of name and diagnosis; 
