Coltus cognatus, &c. with Cottus gobio. 193 
in a point not very sharp. It is not prominent, but easily felt 
by passing the finger from behind forward, covered entirely 
with the skin, and only about one-twentieth of an inch in 
projecting extent. The other is smaller and not so strong; 
it is situated at the anterior inferior angle of the operculum. 
Until the integuments are removed it is by no means easily 
seen, though it can be distinguished. It is not prominent, 
and the finger may be passed over it in the opposite direction 
to that in which it points, that is from before backward, with- 
out detecting it unless close attention is given. When the 
skin, however, is taken off, it is apparent at once. It is only 
about half the length of the preopercular spine, and is less 
curved. These four (two on each side) are all the spines 
that I have been able to detect on the head. The operculum 
ends in a flattened point, but it is not worthy of being called a 
spine, being weak and flexible. 
The skin is smooth, scaleless, covered with a thick mucous 
Secretion. The body tapers from the head gradually ; it is 
Tounded at first, but toward the tail it becomes compressed. 
— The branchial membrane is thin, nearly transparent. The 
fish, like most others of the genus, often inflates it to the ut- 
most when it is taken from the water, and the membrane 
c remains in this condition even after the fish is 
The colors are various, scarcely any two specimens being 
alike in this respect. The younger ones almost always have 
colors more strongly marked than the adult fish, the 
groundwork being lighter and the bands darker. The more 
Senéral arrangement of the colors may, perhaps, be stated 
ds; the prevailing color of the side light yellowish brown, 
With numerous blotches of darker brown, sometimes but not 
-ays amounting to irregular vertical bands which occasion- 
ally cover the greater part of the side. The head is in gen- 
et. darker than the body. The under side of the body, from 
- lower jaw to the caudal fin, is yellowish white. The first 
sal fin is of a light brown, with dark spots, and occasion- 
