FOOD AND PARAi^ITES OF SOME FRESH-WATER FISHES. 



517 



iav into the intestine. In different kinds of lishes, Am la 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 (r', d) examined young specimens of ArnUi and found 

 their food to consist of may-fly larvse, ostracods, and alga% none of 

 which we found in the mature specimens; in older tish he found lish, 

 mollusks, and Crustacea. 



3. Auieiurus nehulosus^ common bullhead. 



The 5 specimens examined were caught in Lakes Mendota and 

 Monona during the months of April, Jul}^, and August. The food 

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

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

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

 of a crawfish. 



The most abundant parasites wxre 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. Trematodes and nematodes were found in the intes- 

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

 lohothridni and a species of P roteoceplialuH {?). 



4. Erimyzon sucetta^ chub sucker, 



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

 parasites only a few Acanthocephala in the intestine. 



5. Ksox Incuts^ common pike. 



The 3.5 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 difi^erent kinds of 

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

 be seen from the followino- table: 



Forbes {c^ d) found the food of the pike to be almost exclusivelj'' 

 otl^pr fish, 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 we examined were exceptional, in that one con- 

 tained 10 and the other 20 minnows. 



