12 MONOGRAPH OP THE FRESH WATER III. 



tute a genus by itself, the genus Triglojpsis associated there with a species of Cottus 

 proper. 



Passing to the western coast of the American Continent, beyond the Rocky 

 Mountains, between the latter and the shores of the Pacific, we shall find in the 

 Columbia Kiver another species with a special combination of generic characters, 

 the Cottopsis asjjer, associated with a yet undescribed species of Cottus proper, col- 

 lected by the naturalists of the United States Exploring Expedition. The pub- 

 lished ichthyology of that exploration will soon make us acquainted with other 

 members of the Cottoid group. 



If we take a glance on a chart at the localities of the North American Conti- 

 nent where Cottoids have been observed, we shall find extensive tracts which still 

 remain unexplored; all the country west of the Mississippi and Ohio, and in a 

 northerly direction to Lake Superior. Then, again, the British Possessions, that 

 region of numberless lakes, must contain some of these fishes, since we see that 

 one species extends as far north-west as Great Bear Lake, the northernmost of all. 

 Between Lake Superior, the mouth of the Columbia River, Great Bear Lake, 

 and Labrador is included a vast area where Cottoids will undoubtedly be found 

 hereafter, as well as within the limits of the western part of the United States, 

 between the Mississippi and Ohio, to the shores of the Pacific. But how far south 

 they occur we cannot yet tell with certainty. We know that fresh water Cottoids 

 belong chiefly to the temperate zone, having been observed from the arctic circle to 

 the 45° of latitude in the eastern hemisphere, and to the 35° in the western hemi- 

 sphere. 



§ 4. Habits, Food, and Use. 



We have not had the satisfaction of observing ourselves the Miller's Thumbs of 

 this continent in their natural medium. All authors agree in saying that clear 

 and limpid waters with stony or sandy bottoms, are the places most preferred by 

 these fishes. The small rivulets of cold water descending along the slopes of 

 mountains are often their favorite residence, although likewise frequently inhabitants 

 of large lakes. They keep sheltered under stones, which must be removed when 

 in search of them. When uncovered, they sometimes dart away with great 

 rapidity, in search of another hiding place ; and sometimes they wait motionless until 

 started. In Europe, there is scarcely a boy living in their vicinity who does not 

 hunt them by uplifting carefully and slowly the stones of the shores of lakes, or at 

 the bottom of rivulets, and transfixing the fish when motionless, by means of a 

 fork attached to a stick. 



They are of little use to man, not to say in the economy of nature. The marine 

 species are dreaded, being exterminated by fishermen, and generally thrown away 

 when sufficiently mutilated. Sometimes, however, we see the head only cut off, 

 and the body brought home for the table. The flesh of the fresh water species is 

 delicate and much esteemed in some countries of Europe, where they occur in large 

 numbers. Undoubtedly they would be much more sought for, if not generally so 

 scarce and of a size too small to repay the trouble of hunting them. In fact, 



