518 



REPOKT OF THE COMMISSIONER OF FISHERIES. 



The kind of parasites and tlicir prevalence in tlie different parts of 

 the alimentarv tract were as follows: 



Every fish examined contained some parasites. Cestodes and nema- 

 todes were present in more than half, while Acanthocephala occurred 

 in but a single fish. It was noticeable that fish cauo-ht in April and 

 May were much freer from parasites than those caught in November. 

 The trematodes were nearly all Azygia tereticoUe. One cestode was a 

 species of Proteoceplxalus. 



6. Pomoxis sjxiroides, calico bass. 



Three specimens of calico bass were caught during July in Lake 

 Wingra, They had plankton onl}" as food. The only parasites found 

 were two leeches, one on the tongue of one fish and one on the roof of 

 the mouth of another, and a few small cysts on the outer wall of the 

 stomach. 



7. AmhlojMtes rupestris, rock bass. 



Sixteen rock bass were caught during May find Juh^ in Lake Men- 

 dota. The food, found in the 13 fish containing any, consisted of insect 

 larvae in 2 and crawfish in 12. The specimens examined b}' Forbes {h) 

 were found to have eaten insect larvee' much oftener than the bass 

 from Lake Mendota. 



Three fish were wdthout parasites. In the 13 in which they were 

 found the distribution was as follows: Trematodes in 1, nenaatodes in 

 3, and Acanthocephala in 12. Almost as noticeable as the fondness for 

 crawfi.sh as food was the prevalence of Acanthocephala; the entire 

 absence of cestodes is also noticeable. 



8. Lepomis incisor^ biuegill. 



Specimens were taken in March, April, and July from Lakes Men- 

 dota and Wingra. Thirty fish were examined, 20 containing food, as 

 follows: 



Thirteen of the fish were entirely without parasites, as far as 'a gen- 

 eral examination showed, and the other 17 contained the following: 



