Til. COTTOIDS OF NORTH AMERICA. 61 
CHAE TER, “Ve. 
ON THE GENUS COTTOPSIS, Girard. 
We have proposed this genus' for the reception of one species placed by its 
author in the genus Cottus, at the time when the latter still included the marine 
species. It differs both from Cottus and Acanthocottus. By its large size it recalls 
to mind the marine species, and by its smooth head, the species of the fresh water. 
Its physiognomy, as a whole, partakes of both of these groups. Yet as it belongs 
to the fluviatile fauna, it is more nearly related to the fresh water species by its 
first dorsal lower than the second, by the structure of the other fins, the opercular 
apparatus, and the shape of the mouth. 
The characters of the genus Cottopsis may thus be expressed: General form 
regular, fusiform, or subeylindrical. Body covered with a skin beset with prickles, 
instead of being smooth and scaleless. Head deeper than broad; shape of the 
head and cleft of mouth like those of Cottus. A preopercular spine only on each 
side; card-like teeth on the palatine bones. 
_ The obtuse head, the cleft of the mouth, which does not extend beyond the 
eyes, the first dorsal lower than the second, and the prickly skin, are the essential 
characters by which this genus is distinguished from Acanthocottus, whilst the 
palatine teeth and the dermic prickles constitute its difference from Cottus proper. 
We have mentioned that in some Cotti teeth began to be perceived on the pala- 
tines, which character we consider as an approximation towards the Cottopsis, in 
which those teeth are fully developed, and perhaps more so in the adult than in 
the immature state. 
Sir John Richardson foresaw the necessity of withdrawing one day the species 
here referred to from the genus Cottus, and suggested? that it would very likely 
be brought into the genus Hemilepidotus, on the ground perhaps of the presence 
in the latter of palatine teeth. But, as he remarks himself, Hemilepidoti have the 
body partly covered with scales, whilst in this case the skin is provided with 
prickles of a peculiar character. The spiny head of Hemilepidotus, as well as the 
fact that it is an inhabitant of the sea, bring that genus nearer the Acanthocotti, 
and is to the latter what Cottopsis is to Cotti. On the other hand, the unique 
dorsal of Hemilepidoti and their palatine teeth, indicate a closer relationship with 
Scorpena, also a marine genus. 
1 Proc. Bost. Soc. Nat. Hist., iii., 1851, p. 505. 
2 Fauna Boreali-Americana, iii., 1836, p. 315. 
