98 FISHES OP ILLINOIS 



of edible fishes of a size to make them available to the smaller 

 carnivorous kinds when the young of the larger species have 

 grown too large to be captured or eaten. They thus not only 

 furnish the necessary food to the smaller aquatic Carnivora, 

 but they ease the way of growth to the largest kinds, all of which 

 pass through a period when they need fish food, but are not yet 

 large enough to capture the prey upon which they chiefly depend 

 when they are themselves adult. Moreover, by their great 

 numbers, by their various adaptations and correspondingly 

 general ecological distribution, and by their permanently small 

 size, the minnows must distract in great measure the attention 

 of carnivorous fishes from the young of the larger species, upon 

 which, without them, the adults of these larger species would 

 fall with the full force of their voracious appetites. By offering 

 themselves, no doubt as unconscious, but sufficient substitutes, 

 they thus help to preserve for their own future destruction, 

 however, be it noticed the young of many species which would 

 otherwise be forced to feed on each other's progeny. It is 

 not too much to say, consequently, that the number of game 

 fishes which any waters can maintain is largely conditioned 

 upon its permanent stock of minnows. 



Owing to their abundance in all situations, the number and 

 variety of their species and genera, and the ease with which they 

 may be collected and preserved, minnows are an admirable 

 group for a study of local distribution and ecological relation- 

 ship, and the data of our collections applicable to such a study 

 have been assembled, for convenient inspection and comparison, 

 in the following tables and lists. 



