520 



EEPOET OF THE COMMISSIONER OF FISHERIES. 



Twentj-two of these lish contained but one kind of food, and then 

 generally but one or two specimens of the latter was large. One bass 

 had eaten 4 minnows and another 2 frogs. 



Forbes {c, d) found that this species of black bass contained about 

 the same variety of food as recorded b}^ us; he found that fish con- 

 stituted the largest percentage of food, and in much smaller quantities 

 crawfish, insect larvs?, and algte. 



None of the bass we examined was free from parasites, the nearest 

 approach being one fish from which we took but a few cysts in the mesen- 

 tery. Cestodes were more prevalent than any other parasites, although 

 Acanthocephala were nearly as numerous. The following table gives 

 the places in which parasites were found, and the number of fish in 

 which each kind w^as present: 



Copepods (Ergasilufi) on gill, 1; ecstodes in ovary, 4; cysts in mesentery, 1; cestodes in body cavity, 

 1; cysts in liver, 2. 



The trematodes were Azygia teretlcoJle^ A. loossii^ Cxcincola imT- 

 vulus^ and Leuceruthrus microj^teri. One of the cestodes was a species 

 of Proteocej)halus. 



12. Perca jiavesceiu^ yellow perch. 



The perch, caught mostly with hook and line, were taken from 

 Lakes Mendota, Monona, and Wingra — all but a few from the first- 

 mentioned lake. The Lake Mendota perch were nearly all caught near 

 the shore, a fcv/ only coming from deep water. An exception to this, 

 however, was a lot of perch, !(> in number, purchased in February 

 from fishermen, who caught them through the ice at quite a distance 

 from shore and in deep water. The food and parasites of these w^ere 

 quite dift'erent from what we found in the others, and, although at 

 present included with the others, separate mention of them will be made 

 later. Excepting these, all were caught in April, May, or July — more 

 during May than at any other time. 



Seventy-two perch were examined, in only 9 of which were para- 

 sites absent. A few of the others had no parasites in the alimentary 

 tract, bat contained cj^sts in the mesentery or liver. Fifty -six of the 

 perch contained food the nature of which we could determine, and of 

 the remaining 16 a few had food remains in the lower part of the 

 intestine or in the rectum nothing as to the nature of which v/as 

 recognizable. The following table gives the different kinds of food 

 and the number of fish in which each kind was found: 



