PREFACE. 
VII 
XoTE. — In our descriptions the length of the fish is always measured 
from the tip of the snout to the end of the last vertebra: tlie caudal 
fin being not included. The expressions “ head 4” or “ depth 4” mean 
that the length of the head, in the one case, or the greatest deptfi of the 
body, in the other, is one-fourth of the length of the fish. “ Lat. 1.” indi- 
cates the number of scales in the lateral line; when, however, the num- 
ber of transverse series of scales between the head and the caudal flu is 
different from the number jiierced by the lateral line we have usually 
given the former number. The meas<iirements given in the text are 
intended to aiiply to mature fishes. Young fishes have usually the 
depth less, the head larger, the mouth smaller, and the eye larger, than 
adult examples of the same species. 
In the synonymy of any species, where an author quoted has used the 
name adopted by us, that name is not repeated. Descriptions not taken 
from specimens, or at least not verified by us, are, in all cases, credited 
to the author from whom they have been copied. 
