Mr.Vicors and Dr. HORSFIELD on Australian Birds. 171 
try have so long and so justly followed. But nothing can be more 
unfounded than such a supposition. Devoted as our leading zoo- 
logists have hitherto been to Linnzus, they have not evinced a 
. more sincere attachment to his precepts than the authors of the 
following Catalogue. In point of fact, the apparent deviation 
from the ** Systema Nature," in our attempt to arrange the 
ornithology of New Holland, and in similar undertakings of the 
present day, will be found, when strictly investigated, to be 
more in word than in reality. It would be superfluous to call 
to the recollection of the Society how important has been the 
increase of knowledge in every branch of natural history since 
the days of Linnieus. That increase, in the particular depart- 
ment upon which we have entered, rendering the subjects even 
now above five times more extensive than when that pre-eminent 
naturalist undertook to arrange them, has raised his subordinate 
groups into groups of a considerably higher value than they 
originally possessed. Those divisions which he instituted as the 
next superior groups to species, and which he denominated 
genera, have swelled out by the vast accumulation of species 
and the endless variety of new forms comprised in them, into 
what are now considered families, or into assemblages of even 
still more extensive signification. In such a change of materials, 
a corresponding change in their denominations appears essen- 
tially necessary : the groups, which were once termed genera, 
require a more comprehensive title; and the before-unnoticed 
modifications of form that spring up and constitute subordinate 
groups among them take the place which they have left, and, - 
assuming the rank, demand the name, of genera. Such, in fact, 
is the natural course of our science; and such will ever be its 
progress, while information continues to increase. 
On our turning to the examination, however, of the original 
groups of Linnzus, limited as they confessedly were in his days 
z 2 as 
