Food Relations of Fresh-Water Fishes. 479 



shad/ the suckers," and the shovel fish ' among the larger 

 species; the darters,' the brook silversides,'' the stickleback," 

 the mud minnows,' the top minnows,** the stonecats," and 

 the common minnows'" generally, among the smaller kinds. 



Our eight specimens of the toothed herring" had taken no 

 fishes whatever; while our nineteen examples of the pirate 

 perch'- had eaten only two per cent. 



Rough-scaled fishes with spiny fins ( Acanthopteri) were 

 eaten by the miller's thumb, the common pike, the wall-eyed 

 pike, the large-mouthed black bass, the croppies, the dog-fish, 

 the common perch, the burbot, the bull-head," the common sun- 

 fish CLcj;o»//s2J('/^/</'^^'^, the small-mouthed black bass," the grass 

 pickerel, the gar, and the mud cat (Leptops). Among tliese, the 

 common perch and the sun fishes'" were most frequently taken — 

 doubtless owing to their greater relative abundance — the perch 

 occuring in the food of the burbot, the large-mouthed black 

 bass, and the bull-head; and sunfishes in both species of the 

 wall-eyed pike, the common pike, the gars, pickerel, bull-heads, 

 and mud cat. Black bass were taken from the common pike 

 (Esox), the wall-eyed pike (Stizostedion), and the gar. 

 Croppie and rock bass I recognized only in the pike. Even 

 the catfishes (Silurid;e) with their stout, sharp, and poisoned 

 spines, were more frequently eaten than would be expected, — 

 taken, according to my notes, by the wall-eyed pike, both black 

 bass, and the mud-cat (the latter a fellow species of the family). 



The soft-finned fishes were not very much more abundant, 

 on the whole, in the stomachs of other species than were those 

 with ctenoid scales, spiny fins, and other defensive structures, — 

 an unexpected circumstance which I cannot at present explain, 

 because I do not know whether it expresses a normal and fixed 

 relation, or whether it may not be due to human interference. 

 It will be shown, however, under another head, that even when 

 the primitive order of nature prevails, the relative numbers of 

 soft-finned and predaceous fishes vary greatly from year to 

 year under the influence of varying circumstances. 



' Dorosoma cepedianum. - Catostomatidn.'. ^Polyodon spathula. 

 *Etheostomatinai. '^ Labidesthes sicculus. '^Eucalia inconstans. 

 ' Umbra limi. ^Zygonectes. 'Noturus. " Cyprinidse. "Ilyodon 

 tergisus. '^ ^\^piire(joderus sayanus. ^^ Amiurus nebulosus. "Micvop- 

 terus dolomiei. ''^ Centrarchida?. 



