34 
The Food of Fishes. 
difference in color is probably due partly to the smaller 
amount of light to which those inhabiting the deeper wa- 
ters of the lake are exposed, and partly to their pisciv- 
orous habit combined with the comparatively few lurking 
places afforded them. There is some evidence that fish 
food bleaches a fish directly, and a good deal that it does 
so indirectly, by increasing the importance of an incon- 
spicuous appearance. 
Stizostethium canadense, Smith. Gray Pike-Perch. 
Sauger. “ Jack-salmon / 9 
Fourteen specimens of this excellent fish were exam- 
ined, all of which were from the Illinois R., ten taken in 
October, 1878, one in June, 1877, and three in November, 
1877. It is evidently a very destructive species. These 
specimens had eaten nothing but fishes. In three cases 
these were unrecognizable, and in two others I could only 
tell that they were Acanthopteri. Four of the remaining 
‘‘pike” had eaten hickory-shad {Dory soma cepedianum ) , 
two had eaten catfish (Siluridse) of which one was an 
Amiurus, two had eaten sheepshead {Haploidonotus 
grunniens ) , and one had taken a black bass and some sun- 
fish (Centrarchidse). The presence in the stomach of one 
of these fishes, of a catfish of medium size, with its poison- 
ous pectoral and dorsal spines unbroken, was a striking 
illustration of the gastric energy of this species. 
Stizostethium vitreum, Mitch. Pike-Perch. Wall-eyed 
Pike. “Salmon.” 
This is far the finest of our river fishes — second to no 
fresh-water species except, possibly, some of the salmon 
family. It occurs in the great lakes, and throughout the 
State generally in the larger streams. It is a much larger 
fish than the preceding, not infrequently reaching a 
weight of twenty pounds. Certainly no fish of our waters 
is better deserving of attention than this. The only draw- 
back to its increase is in its voracity ; but, although it de- 
vours an immense number of other fishes, there is no evi- 
dence that it is wantonly destructive or that it eats more 
in proportion to its weight than the black bass. 
