The Food of Fishes. 
37 
period, can probably be more readily maintained in large 
numbers in our muddy streams than any other fish. 
It is evident that the increase of edible fishes without a 
corresponding supply of food will be largely time and 
labor thrown away. Probably if protected from wanton 
and ignorant destruction, the Dorysoma would abound 
sufficiently, as it is enormously prolific. 
The following table is similar to that given for the pre- 
ceding family. The mark j* is used to indicate the occur- 
rence of an element in too small an amount to figure in 
the ratios. 
