FOOD AND PARASITES OF SOME FRESH-WATER FISHES. 



517 



fa)' into the intestine. In different kinds of fishes, Auda included, it 

 was noticed that the cestodes apparently moved forward in the ali- 

 mentary^ tract after the death of the host, often protruding into the 

 mouth. Forbes (c', d) examined young specimens of Ainia and found 

 their food to consist of may -fly larvae, ostracods, and algje, none of 

 which we found in the mature specimens; in older iish he found fish, 

 mollusks, and Crustacea. 



3. Aniehinis nchulosus^ common bullhead. 



The 5 specimens examined were caught in Lakes Mendota and 

 Monona during the months of April, July, and August. The food 

 contained in the different parts of the alimentary tract was in such a 

 condition as to make impossible a determination of its separate parts. 

 In oiie fish a minnow could be recognized and in another the remains 

 of a crawfish. 



The most abundant parasites were cestodes, found in the intestine 

 of 5 fish, 3 of these also containing them in the body cavity. Acan- 

 thocephala were found in large numbers in the intestine of 4 fish, 

 liver cysts in 4. Trematodcs and nematodes were found in the intes- 

 tine of but a single fish. The cestodes found were 2 species of Coral- 

 lohotJiriuni and a species of Proteoceplialus {?). 



4. Erbnyzon sucetta^ chub sucker. 



A single specimen caught in April was without food and had as 

 parasites only a few Acanthocephala in the intestine. 



6. Esox Jucins^ common pike. 



The 35 specimens examined were all taken from Lake Mendota 

 during April, May, oi' November. Thirteen of the entire number 

 were without food, the remaining 22 showing either a small or a large 

 quantity of food within the alimentary tract. The different kinds of 

 food, and the number of fish in which each kind was found, can readily 

 be seen from the following table: 



Forbes (c, d) found the food of the pike to be almost exclusively 

 otl\er fi.sh, this being true of 36 of the 37 specimens he examined. It 

 will be seen at once that our results are almost identical, but 2 of the 

 35 pike examined by us containing any food other than fish. We also 

 found that as a rule but one or two fish were present in the alimentary 

 tract; 2 of the pike w^e examined were exceptional, in that one con- 

 tained 10 and the other 20 minnows. 



