III. COTTOIDS OF NORTH AMERICA. 01 



CHAPTER IV. 



ON THE GENUS COTTOPSIS, Girard. 



WE have proposed this genus 1 for the reception of one species placed by its 

 author in the genus Coitus, 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 subcylindrical. 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 Acauthocottus, 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 Eichardson foresaw the necessity of withdrawing one day the species 

 here referred to from the genus Cottus, and suggested 2 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 

 Scorpcena, .also a marine genus. 



* Proc. Bost. Soc. Nat. Hist., iii., 1851, p. 303. 

 2 Fauna Boreali-Americana, iii., 1836, p. 313. 



