CTPEINIDiE — THE MINNOWS AND THE CARP 97 



Only two of these 24 species were most abundant in the 

 larger rivers, and 6 in the smaller rivers. Fourteen species were 

 found most frequently in creeks, 1 was most abundant in lakes, 

 another in the bottom-lands, and another in clear upland lakes. 

 If we may take our miscellaneous collections to have been fairly 

 distributed as to varieties of situation and to proportionate 

 extent of each variety, we may further infer from our data that 

 minnows will generally be found over a relatively hard and clean 

 bottom about two and a half times as abundantly as over a 

 bottom of mud. 



In the general scheme of aquatic life, the native members of 

 this family, taken together as a group, play a multiple role. 

 They operate, to some extent, as a check on the increase of the 

 aquatic insects, from which they draw a large part of their food 

 supply; they make indirectly available, as food for their 

 own most destructive enemies, these aquatic insects, man}^ 

 terrestrial insects also, which fall into the water and are 

 greedily devoured by them, and the mere mud and slime and 

 confervoid algae gathered up from the bottom of the waters they 

 inhabit; and they rival the young of all larger fishes, their own 

 worst enemies included, bj^ living continuously, to a great 

 degree, on the Entomostraca and insect life which these fishes 

 must have, at one period of their lives, in order to get their 

 growth. They also offer a considerable means of subsistence to 

 certain aquatic birds, such as kingfishers, and members of the 

 heron family; and, through their contributions to the support 

 of the best food fishes, they form an important link in the chain 

 of agencies by which our waters are made productive in the 

 interest of man. 



Among the enemies of Cyprinidce disclosed by our study of 

 1,221 Illinois fishes, already referred to, are practically all 

 our most predaceous fishes, including the dogfish, both our 

 common species of gar, the wall-eyed pike, both our species of 

 pickerel, both species of black bass, the yellow perch, the mud- 

 cat, the bullheads, the crappies, the green sunfish, and, finally, 

 one of their own family, the horned dace. That this list might 

 be considerably enlarged by more extensive studies of the food 

 of fishes is beyond a doubt, and it is safe to say that no fish- 

 eating fish would, if hungry for fish, refuse a minnow of any kind 

 unless it seemed too small to be worth the trouble of capturing. 



From the standpoint of the predaceous species, minnows are 

 young fishes which never grow up, and thus keep up the supply 



