234 



BULLETIN OF THE BUREAU OF FISHERIES. 



Like the bluegill, the pumpkinseed is found only in shallow water and among vege- 

 tation, but may occur wherever these are found in the lake. 



The contents of the alimentary canal were examined in 9 individuals. In 6 

 small snails and their crushed shells were found. In 4 of the 6 the alimentary canal 

 contained no other material than the snails; while in the fifth it contained in addition 

 to the fragments of 3 small snails a quantity of Chara with orange fruits. The Chara 

 may have been adventitious. One stomach contained insect larvae exclusively; one 

 contained insect lan^a; in addition to snails; and a third insect larvae, snails, and other 

 material. Snails appear to be the most important element of the food and next to these 

 insect larvae, but exact percentages are not available. The snails found in no. 8, 11, 

 and 12 were determined by Mr. H. B. Baker to belong to the species Amnicola limosa 

 and Planorbis btcarinata portagensis. The former were adults from one-sixth to one- 

 eighth inch long, while the latter were young individuals. Forbes and Richardson 

 (1908) found that snails made up nearly half the food of 9 specimens examined by 

 them, insects a fifth, and Crustacea a fifth. Hankinson (1908) examined 32 stomachs 

 and found May-fly lan,'ae to be the favorite food, although Crustacea, snails, leeches, 

 and other insects were included. The evidence on the whole indicates that snails are 

 the most important element in the food. Fishes appear not to be taken. 



Hankinson gives the length of 16 specimens and their average is 5.8 inches, includ- 

 ing the caudal fin. The length without caudal fin as determined from figures forms 84 

 per cent of the total length, which makes the average of Hankinson's specimens 5.1 

 inches without caudal fin. Our Douglas I^ake specimens average 5.2 inches. Judged 

 by this standard, the conditions are about as favorable in the one lake as in the other. 



The pumpkinseed appears to be more resistant to foul water than the bluegill. 

 When numbers of each were placed together in a pail of water, all the bluegills were 

 found dead after a time, while the pumpkinseeds were still active. 



MiCROPTERUs DOLOMiEu Lacepede, small-mouthed black bass. — The Douglas Lake 

 data on this fish are given in table vii. 



Table VII. — Records of Micropterus dolomeu Taken in Douglas Lake. 



The small-mouthed black bass is found over a large part of the lake, but anglers 

 seek it along the lakeward margin of the patches of aquatic vegetation, where it is most 

 abundant. Our data show that in midsummer it ranges to a depth of 45 feet, that is, to 



