6 TWELFTH ANNUAL RIPORT. 



tacean forms which are, perhaps, most typical, abundant and 

 interesting of the smaller animals of fresh waters, it is to be re- 

 marked that they are of a practical value to an extent which can 

 hardly be correlated with their seeming insignificance. 



To understand this fact it is first necessary to recollect that 

 water in some form is an indispensable vehicle for the nidus of 

 disease germs as well as of all life; desiccation means death. The 

 abundantly-watered portion of our country must become per- 

 meated with the pestilential hordes ingendered in its fens did not 

 this army of devouring animalculse destroy the decaying matters 

 accumulating in the waters. 



Their importance depends largely on their minute size and un- 

 paralleled numbers. The majority of non-carnivorous crustaceans 

 are so constituted that their diet is nearly confined to such floating 

 particles of matter as are present in the water, in a state of more 

 or less fine comminution; for, nearly without prehensile organs, 

 these animals, by means of a valvular or, at most, ladle-like labrum, 

 dip from the current of water kept flowing by the constant 

 motion of the branchial feet, such fragments as the snail and 

 scavenger-fish have disdained. All is fish which enters the net. 

 Think of it, poor dyspeptic, a constant supply of food of every 

 variety and no question asked for stomach's sake! Bits of decay- 

 ing algae or the broken fragments of a disintegrated mosquito, all 

 alike acceptable aad unhesitatingly assimilated. 



Nor is the sanitary aspect the only one in which the entomosU 

 raca^ as our minute Crustacea are collectively called, command 

 attention; they are valuable also as a food supply. 



Now, does some one jump at the conclusion that the water we 

 drink is filled with aliment in such pleasant form as that repre- 

 sented above — that Dr. Tanner after all lived on a watery solution 

 of entomostraca? Too fast, my friend — food for fishes, but not 

 therefore an insignificant element in our cuisine economy; for it 

 has recently been shown by Prof. Forbes of Illinois, that some of 

 our best fresh-water food fishes are almost dependent on some one 

 or more species of entomostraca. Darwin shows that cats regulate 

 the clover crop of England via field-mice and humble-bees, but it 

 is not half as far from our ''bugs" to the price of trout and white- 

 fish. 



Still we are not prepared to be surprised at this, for have we not 

 long understood that whales go fishing, with their whalebone nets, 

 for little mollusks not big enough to excite the cupidity of the 



catorial small boy ? 



