82 INTRODUCTION. 
expect to cause a reform, but we hope that, among 
the numerous young zoologists who are now coming 
forward, there may be some who may concur in the 
justice of our opinions, and whose career may be, 
cither through conviction or unconsciously, influenced 
thereby ; and we shall be happy if in a single instance 
we shall prevent a repetition of the evils which we 
have mentioned. 
As to the application of our own principles to the 
species treated of in this work, we would remark, that 
among our generally acknowledged species, there are 
some which seem to us to be separated from others 
on insufficient grounds, and that our inclination is 
in every such case to reunite them. In some of these 
instances our opinion is confirmed by the opinion of 
gentlemen whom we consider to be better qualified 
than ourselves to decide ; in such, of course, there is 
no doubt. In others, that sanction is wanting or doubt- 
fully yielded ; yet our own convictions are too strong 
to permit us to hesitate. But in another class of 
cases, we are opposed by the unanimous opinion of 
all those zoologists who are familiar with the subject. 
Here, we yield our own belief to the common senti- 
ment. We do it the more willingly, because time 
cannot fail to develop further facts which will estab- 
lish the truth ; and because multiplied observations on 
the characters and habits of species are necessary, 
and investigations must be made in some unexplored 
parts of our country before we shall possess the ma- 
