520 
ACCOUNT OF SOME FISHES 
line, and cover the whole cheek. The prae-operculum tri- 
angular, larger arid stronger than the operculum, curves 
down upon the bronchiostegous membrane, and has a pearly 
lustre. A narrow, somewhat cartilaginous, border forms 
the posterior rounded margin of the operculum. 
The eye is large, and its orbit approaches very near the 
margin of the mouth. 
The nostrils are double, and placed above the angle of 
the eye, near the extremity of the snout. The valve of the 
posterior nostril is formed out of the membranous border of 
the anterior one. 
The mouth is large for the size of the head, and its ori- 
fice descends obliquely downwards. When the jaws are 
extended, the upper one is nearly vertical, forming an angle 
of 70° with the lower one, which stands horizontally, and 
consequently appears the longer of the two. The maxil- 
laries enter rather more largely into the composition of the 
margin of the mouth than the intermaxillaries. Both are 
narrow : the former linear, nearly immoveable, and articu- 
lated with the latter, whose somewhat dilated extremities 
project a little over the lower jaw, and move shghtly for- 
wards when the mouth opens. 
Teeth, — The upper jaw is armed with a single row of 
conical teeth, the intermaxillary ones being considerably 
the largest. The lower jaw is strong, and armed with a 
double row of conical teeth, having their points directed 
backwards. Betwixt these two rows there is a narrow, bony 
surface, rough, with minute teeth. The vomer projects 
from the roof of the mouth, and is armed, like the lower 
jaw, with rows of strong conical teeth, and intermediate 
card-like plates. The palatine bones are rough, with mi- 
nute teeth. The largest teeth of all are hook- shaped, and 
situate upon the margin of the tongue. The centre of the 
