Mavor & Strasser—Urinary Bladder of Wisconsin Fishes 557 
PAPERS CITED 
Auerbach, M.—1910. Die Cnidosporidien, Leipzig. 
Mavor, J. W.—1916. On the occurrence of a parasite of the 
pike in Europe, Myxidium lieberkiihni Biitschli, in the pike on 
the American continent and its significance. 
Mavor, J. W. and William Strasser.—1916. On a new myxos- 
poridian, Henneguya wisconsinensis n. sp., from the urinary 
bladder of the yellow perch, Perea flavescens. 
DESCRIPTION OF PLATES. 
All drawings were made with the camera lucida from fresh 
preparations of the urine. 
PLATE I. 
Fig. 1. Henneguya wisconsinensis from Micropterus sal- 
moides.- Plasmodium. No differentiation into ectoderm and en- 
doderm visible. X970. 
Fig. 2. Henneguya wisconsinensis or Myxidium salvelini 
from Salvelinus fontinalis. X2500. 
Fig. 3. Henneguya wisconsinensis or H. sp. from Lepomis 
pallidus. Plasmodium. Ectoplasm and endoplasm are differen¬ 
tiated and there are no larger granules. X2200. 
Fig. 4. Henneguya ivisconsinensis from Micropterus sal- 
moides. Plasmodium. Ectoplasm and endoplasm are differ¬ 
entiated and there are fine pseudopodia for attachment to the 
bladder wall. X970. 
Fig. 5. Myxidium salvelini from Salvelinus fontinalis. Plas¬ 
modium. There is no differentiation into Ectoplasm and endo¬ 
plasm. The pansporoblasts are in various stages of development 
into sporoblasts and spores. X970. 
PLATE n. 
Fig. 6. Henneguya wisconsinensis from Lepomis pallidus. 
Plasmodium. The protoplasm is divided into ectoplasm and 
endoplasm. The endoplasm is finely granular and contains larger 
greenish granules of varying size. The plasmodium contained 
a single spore. X1250. 
