170 Wisconsin Academy of Sciences, Arts, and Letters. 
1921, pp. 19, 58). Detailed accounts of the general characteristics 
of these lakes and of routine catches in them have been published 
(Pearse, 1921, 1921a). 
Green Lake and Lake Mendota were studied during August, 
1919. The lakes investigated in 1920 were studied as follows: 
Pepin: June 20 to July 25; Lake Michigan: July 27 to August 7; 
Geneva: August 8 to 25. 
Attention will now be directed to a detailed consideration of 
the parasites that were found to infest Wisconsin lake fishes and 
the parts of fishes’ bodies that they frequented. Although un¬ 
identified parasites of various groups occurred in a number of 
fishes, they are not given in the following lists. 
Protozoa 
Myxobolus cysts were found once in Lake Mendota on the gills 
of a yellow perch. Doubtless other protozoan parasites occurred, 
but were not observed. 
Trematoda 
Acetodextra amiuri Pearse 
Found in the swim bladders of the yellow, black, and speckled 
bullheads in Lake Pepin; in the black and speckled bullheads in 
Lake Michigan. 
Acrolechanus petalosa (Lander) 
Common in the sand sturgeon in Lake Pepin. 
Allocanthocasmus varius Van Cleave 
Occurred in the white bass in Lake Pepin; free in the intestine 
and encysted in the liver. 
Allocreadium armatum (MacCallum) 
Found in intestine of the sheepshead in Lake Pepin and Lake 
Michigan. 
Allocreadium holeosomi Pearse 
In intestines of the Johnny darter and log-perch in Lake Pepin. 
