212 College of Forestry 
The number of molluscan species eaten by a species of fish 
is noteworthy; thus, the Pumpkinseed is known to eat 18 
species, Whitefish 17, Yellow Perch 8, Common Red-Horse 
10, Common Bullhead 11, and Channel-cat 8 species. 
Upwards of 40 species of mollusks are now known to be 
used as food by fishes, and this number will doubtless be 
largely increased with further investigation. In the light of 
our present knowledge the relative importance in descending 
order, of the different molluscan genera as food for mollusk- 
eating fish stands as follows: Pisediwm, Spherwum, Amnicola, 
Valvata, Physa, Planorbis, Galba, Bythinia, and Musculiwm. 
There is need for greater accuracy in the determination of 
the molluscan contents in the food of fishes, many authors 
being content with simply reporting Mollusca, Gastropoda, 
snails, bivalves, or simply the genus, as Planorbis, Valvata, 
Amnicola, Vurpara, ete. As the fishes discriminate as to 
species among these genera, it 1s of importance to know pre- 
cisely what species or even race is represented. 
Foop anp Game Fisures Frrprina Upon Mo.uusks. 
In Table No. 12 are listed (after Forbes and Richard- 
son, 1909, p. CXIX) in the order of their importance, 
economically, the food and game fishes of New York, 25 in 
number, that feed upon mollusks. This list includes a 
majority of this class of fish and illustrates graphically the 
importance of the mollusks (shellfish) as a source of food 
supply. Among the fishes of the first class the mollusean food 
is 19 per cent. and of the second class it is 28 per cent. In 
some cases, as in the Round Whitefish and the White Bass, 
the percentage has not been stated, although known to be 
large. In the third class the total percentage is over 50 per 
cent. and in the fourth class is upwards of 29 per cent. The 
average per cent. for the 25 species is 31.50, or about one- 
third of the food. 
