Mavor & Strasser—Urinary Bladder of Wisconsin Fishes 553 
STUDIES OF MYXOSPORIDIA FROM THE URINARY 
BLADDERS OF WISCONSIN FISHES 
By J. W. Mayor and W. Strasser. 
1. Introduction. 
Considerable interest is attached to the geographical distribu¬ 
tion of protozoan parasites and their occurrence in different spe¬ 
cies of hosts. The present paper gives the results of examina¬ 
tions of the urinary bladders of some of the commoner species of 
fishes occurring in the lakes surrounding Madison, Wisconsin. 
In all, five species of fish have been examined and four species of 
myxosporidia have been found. One of these, Myxidinm lieher- 
kiihni, occurs in the pike» Lucius lucius in both Europe 
md America. The other three are described as new species. 
The attempt has been made to find characters which distinguish 
the plasmodial stages of the different species. 
2 . Methods. 
The work of examining the urinary bladders has been much 
facilitated by the employment of a method which does not in¬ 
volve the killing of the fish. A fine glass canula, provided with 
a rubber tube to which suction could be applied by the operator, 
was inserted into the bladder of the fish through the urino- 
genital opening. In this way a small quantity of the urine with 
the contained myxosporidia could be drawn into the canula, and 
by working the canula against the walls of the bladder attached 
forms could also be obtained. It was found that the urine could 
be kept in the canula for one or two hours without injury to the 
plasmodia. Fresh preparations were made from the urine. The 
‘ ‘ hanging drop ’' method was found to be the best; a small quan¬ 
tity of urine was spread on the center of a coverglass which was 
