vi PREFACE. 
every systematist, although too many of them are apt to forget 
this true end, and to think only of the means of elevating them 
selves, at the expense of their predecessors and of the unhappy 
student, who becomes bewildered in the ehoice among so many 
different systems, each carefully shrouded in the veil of its own no- 
menclature. 
After this strong but reluctant expression of my opinion with 
respect to the growing practice of unnecessarily altering generic 
names, it may be expected that I should state my reasons for 
having in a very few instances ventured myself to reject the 
generic names of others and to propose new ones in their place. 
But these are cases of a very different character, in which the re- 
tention of the older names would be calculated to give rise to am- 
biguity, and thus to defeat the very object for which “proper” 
names are used. They consist of two classes: in the first the same 
name has been previously employed in other branches of Natural 
History; and such repetitions have an obvious tendency to create 
confusion. “ We should,” says Mr. Swainson, “ not know, in fact, 
which was intended, a butterfly or a plant, a quadruped or a spider. 
When such repetitions are discovered, the name first imposed or 
employed is to be retained, and a new one given to the other group. 
Thus Urania in Entomology is an old genus in Botany, it is there- 
fore now changed to Letlus ; Lophyrus in Ornithology, an old genus 
in Entomology, is now changed to Péilophyrus.” The sanction of 
authors of note to changes so imperatively called for has induced 
me in this general view of Ornithology to follow their example 
by striking out such equivocal names; but I have always en- 
deavoured, where it was possible, to supply their place with names 
from the older authors, in preference to inventing new ones of my 
own. The second class comprehends a few generic names, differing 
only in termination from others previously in use, and consequently 
liable to be confounded with them. Here again I have the sanction 
of high authority for this very necessary change. Thus the name 
of Ocypterus has been rejected by Dr. Horsfield, who has substituted 
for it that of Lentopteryx, a genus under the name of Ocyptera ha- 
ving been previously established in Entomology ; and Alectura has 
been changed by Mr. Swainson into Catheturus, on account of the 
