S. H. Scudder—Canons of Nomenclature. 349 
first and prime rule of the code accepted by the British Associ- 
ation, with the exception of certain references made exclusively 
to species; and, since this canon meets universal acceptance, 
there is no need of discussing it, aside from the following limit- 
ations. ? 
1. This law of priority should not extend to works published 
before 1758. 
The same reasons for such a limitation do not exist in the 
present instance as in the case of specific nomenclature; but sim- 
ilar objections can be made to an earlier limitation. Only three 
reasonable courses are open to the naturalist: to accept (a) no 
limitation whatever, in which case “ our zoélogical studies would 
frittered away amid the refinements of classical learning ; (6) 
the limitation here formulated, in which case all our systematic 
nomenclature takes its common origin in the tenth edition of 
Linné’s Systema Nature ;* or (c) to apply the laws of nomen- 
clature to each kind of group (subfamily, family, class, etc.), 
from the time when such group was first brou ht into use— 
which would engender such confusion as speedily to bring all 
nomenclature into deserved disrepute. 
2. Plural or collective substantives (or adjectives used as 
substantives) are alone admissible. 
the higher groups are all collective—in idea, if not in 
fact—it is essential that the names applied to them should be at 
formed should be dropped. The retrospective action of such a 
law would be very slight. 
3. A name which has been previously proposed for some 
genus or higher group in zodlogy should be expung' : 
This accords too well with accepted rules to require any dis- 
cussion, 
4. When two authors define and name (differently) the same 
group, both making it of the same or very nearly the same ex- 
tent, the later name (or if synchronous, the least known name) 
hould be cancelled, and never again brought into use. _ 
_ With the exception of certain verbal modifications, this law 
18 identical with the sixth section of the British Association 
rules, where it is applied to genera only. 
_ 5 In any subsequent alterations of the limits of a group, 
its name should never be cancelled; but should be retained 
either in a restricted or an enlarged sense. i 
_rhe necessity for such a limitation is obvious; otherwise a 
different name would (or, could) be given by every author who 
* The English—the strongest f the plan of dating from the twelfth 
edition of the Systema Wateads ksh owe oy aarioas scouting the earlier date of 
t 158 as the starting point for zoological nomenclature, and we may assume that, 
'n this view, the whole scientific world will sooner or later coneur. 
