ADVERTISEMENT. 
^ill be fuithermore perceived, that, independently of a 
ew of the more abundant kinds of the fish tribe, wliich, 
as aheady intimated, were purposely omitted, others, 
considered lare, aad described as such by several writers, 
jiave een excluded. The latter omissions, we feel some 
t,iatifieation in stating, have rarely arisen from the want 
o the particular subjects intended, or even in many in- 
stances the individual specimens, or drawings, to which 
t le respective writers refer, but because there appeared 
some weighty or sufficient reason for believing them inad- 
missible into a work of this nature. 
There is indeed too much cause to apprehend, that our 
e^ historians on the subject of British Ichthyology have 
fm ^^^^•^'iselves in various instances to be misled, and 
n tie want of opportunity, or inclination in their suc- 
s to investigate the truth, the mistakes of one writer 
ve lecome confirmed by the subsequent testimony of 
lers, and thus varieties, or even species, are established, 
1C 1 have existence only in the writings of the authors by 
■'v om they are described. Errors of this kind are immedi- 
ate y within our knowledge, and which we cannot hesitate 
to consider of such serious moment as to require particular 
mention in this place. M'e really disclaim every allusion to 
t e general veracity of the respectable writers involved in 
t us explanation, but feel at the same time that we ought 
not, consistently with our desire of promoting science, lend 
oui countenance to error when it remains in our power 
to correct it. 
Eroni the time even of the illustrious Ray it is strongly 
suspected that some few of the errors alluded to have 
b 2 
