30 
the subject he remarks that it is of little moment whether 
the Orders be few in number or not, but that one ad- 
vantage will accrue from their being few, in that the 
difficulties of drawing the natural boundary-lines be- 
tween the Genera vary directly with the number of the 
Orders. 
It was in very truth a great step forwards in the 
development of science that ARTEDI had herewith taken. 
Fully grasping the state of confusion that prevailed in 
natural history systematics and nomenclature as he 
found them, he made bold to urge the necessity of a 
thoroughly systematic classification, demanding at one 
and the same time "classes naturales", "ordines natu- 
rales", and "manipulos naturales"; this he did, it is 
true, primarily for fishes, because his whole work deals 
with them, but, as pointed out above, he repeatedly as- 
serts that the same thing holds good "etiam in reliqua 
Historia naturali". He goes, indeed, still further, for 
he also desires to obtain "genera naturalia"; the correct 
determination of these, moreover, he seems to have re- 
garded as of the utmost importance, speaking of it as 
the chief aim and object of the whole science of Ich- 
thyology. 
The discussion that ARTEDI then proceeds to enter 
into as to what is to be understood by Genus, was by 
no means out of place at the time he was writing, for 
the genus-notion, though not wholly unknown, had 
never been clearly grasped or defined. ARTEDI says about 
it: -- "Genus in Historia naturali est Analogia qusedam 
Specierum certarum, quse in Figura, Situ, Numero vel 
Proportione Partium ita conveniunt, ut ab omnibus ali- 
orum generum speciebus in aliqua minimum parte dif- 
ferant." This definition, which has general application 
in Natural History as a whole, is followed by one spe- 
cially adapted to Ichthyology: 1 "Genus Ichthyologiae est 
convenientia qusedam certarum specierum, seu simili- 
1 There exists a certain similarity in wording between this de- 
finition and that given in 167 of LINNAEUS' "Fundamenta Botanica". 
hence L., in editing A.'s work, added a reference to his own. 
