32 
seous fishes is to be looked for in the number of the 
branchiostegals of the gill-membrane, though regard 
must also be paid to the general appearance, the posi- 
tion and number of the fins, the place of the teeth, the 
shape of the scales, and other external features, nor 
should the importance in this regard of certain internal 
anatomical characters be lost sight of, such as the stom- 
ach, the caecal appendages of the pylorus, the intestines, 
the bladder, etc. 
By following the rules laid down by ARTEDI and 
their corollaries, the scientists who came after him were 
able to differentiate the genera of fishes one from an- 
other. In order, however, that the notion of genus 
might have accorded to it the full value it deserved, it 
was necessary, as ARTEDI clearly perceived, to establish 
certain definite genus-designations. This was a com- 
plete novelty, and one of the utmost significance. Pre- 
vious to his time nothing of the sort had been con- 
ceived, which is of course not to be wondered at, seeing 
that the very notion of genus had not as yet become 
an integral part of the zoologist's system of classification. 
Up to that time it had been usual to identify any par- 
ticular fish by citing a long list of synonyms, accom- 
panied by a more or less lengthy series of descriptive 
epithets. 1 Now, on the other hand, it is ordained that 
to every genus a name shall be given consisting of one 
word only, whereby all the species belonging under that 
genus shall be known and distinguished. Furthermore, 
the rules of nomenclature are also stated, in order that 
the new system may be the more firmly established. 
There was every reason for ARTEDI to adopt radical 
measures for imposing his reforms upon ichthyologists; 
the names used at his day presented a picture of in- 
credible confusion and muddle; for fishes belonging to 
1 As a typical example may be here cited the notation given 
for cod by WILLUGHBY and RAY in the work quoted above: "Asel- 
lus major vulgaris, Belgis Cabilrau, Mohrua vulgaris (maxima Asel- 
lorum species) Bellon. Molva vel Morhua altera minori Rondel. Gesn. 
p. 102 Aldrov. lib. 3 Cap. 6. A. Cod-fish, or Keeling". 
