Nomenclature and Priority. XXXVIl 
recognizable. The descriptions doubtfully recognizable are 
found in the old books. Therefore any expedient which ex- 
cludes recourse to the old books effects the object. 
The object also is to preserve the names which are every- 
where in use. Any expedient, which protects the names in 
use, ex vi termini excludes doubtful names brought up from the 
old books. 
The objects are clear—(1) to exclude doubtful names; (2) to 
preserve accepted names. ‘They are not identical, but both 
objects can and must be pursued together. 
It has been several times suggested that the enjoyment of 
universal acceptance for a period of years should give a name 
an indefeasible title to adoption. For a purpose which I have 
in view, I will fill in the number “thirty ” and make the pro- 
posal read thus: No name for thirty years in universal accept- 
ance should be displaced. 
We have seen that an objection which we had to meet was 
fotinded on the claim for justice to predecessors. A part of our 
reply was that the “justice” demanded was demanded under 
ex post facto legislation—the “rights” being laid claim to 
under a retrospective construction of the law. 
If that answer recommends itself, then we advance a step. 
No rights can justly be claimed under a retrospective construc- 
tion. Acton that. Deny to the law any retrospective opera- 
tion. See now whether we are not rewarded for consistent 
conduct by seeing our difficulties disappear. 
The date of the law is 1842, a year which is a good way on 
the right side of the ‘infancy of science” period, to which we 
owe our troubles. No name before 1842 can lay claim to 
priority as a right. 
This would be the working of the limitation. No name 
could be produced now for the first time from any book bearing 
date 1842 or previously. Place together by themselves, 
labelled ‘Old Style,” all books of that period, and agree that 
they be considered as non-existent so far as new identifications 
are concerned. ‘That stops the evil spreading henceforward. 
No author can then bring up a name from Old Style books, 
unless the name has been kept alive by quotation as the true 
name in some work since 1842. Here is a measure there is 
really no difficulty in applying, and its operation is simple. 
Merely being quoted in the synonymy since 1842 will not do. 
Nearly all these names which afflict us (now brought forward 
as the true names) have for years past appeared in the 
synonymy as representing some species in some author. If 
that were allowed to give the old name a claim to be received, 
we should reap little benefit from the change. 
This limitation agrees well with the proposal already men- 
tioned, which has attracted much popularity. The names which 
have appeared as the true names in publications since 1842 fall 
