A Revision of the Genera of the Aranez. 51 
IX.—A Revision of the Genera of the ARANEX or Spiders 
with reference to their Type Species. By F. O. Pickarp 
Campripa@s, B.A. 
Iv might have been supposed that with Thorell’s work on 
the genera of European Spiders, in which the types have 
been selected, written in 1869-70, and with Simon’s splendid 
volumes on the genera of the world, with the types also 
selected, appearing at intervals from 1892 onwards, that 
any revision would be unnecessary, and would simply mean 
doing over again work already admirably accomplished. 
In the first place, it must be pointed out, however, that 
neither of these two authors was apparently aware that the 
types of twenty-nine genera had been definitely selected by 
Latreille in 1810. They are selected at the end of his work 
‘Consid. gén. Nat. Ord. Crust., Arachn. et Insectes,’ in the 
“Table des genres avec l’indication de l’espéce qui leur sert de 
type.” Itis true that the types are selected under the French 
form of the generic name, but since both the Latin and French 
forms are given in the earlier systematic part of the same 
work, there cannot be the slightest doubt as to what is the 
signification of the names and what particular group the 
selected type represents. 
Thorell, too, allowed himself sometimes to be influenced 
by what authors themselves would have wished with regard 
to their published names and species, forgetting that when 
a name has once been published it becomes public property 
and the author has no further rights over it. He, for 
instance, in the case of Micromata, Latreille, says that a 
certain species, accentuata, “ got in by mistake” and must 
therefore be ignored. On those principles there is nothing 
to prevent any author making the same assertion of any 
species or any number of them originally referred to any 
genus. Thorell, moreover, has in some cases been content 
with deciding that such and such genera are synonyms of 
others, and has therefore refrained from selecting the types. 
Since, however, genera dropped in haste are apt to be later 
on restored at leisure, it is very important to know what are 
the type species which represent them, whether they are 
eventually to stand or not. 
He does not, however, come to any conclusion without 
giving his reasons very fully, and thus it becomes much 
easier to revise his work and bring it up to date. 
The same remarks apply also to some extent to Simon’s 
work. He, too, set out apparently with some definite principles, 
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