Mavor — Strasser—On a New Myxosporidian. 681 
of No. 13 (Gurley, 1894, p. 246, PI. 30) are very similar in 
shape and size to those of our parasite but are not so wide. 
No description is given by Borne of the parasite recorded by 
him, No. 12, from Leuciscus rutilus . 
No species of Henneguya or other myxosporidian is re¬ 
corded as occurring in the urinary bladder of the European 
perch, Perea fluviatilis, L., the only species of myxosporidian 
recorded from this fish being Henneguya psorospermica testa 
L. Cohn and H. psorospermica minuta L. Cohn, both from 
the gills. The spores of H. psorospermica testa L. Cohn are 
described as similar to those of H. psorospermica typica 
Thel., which measure 29-38 n by 15-20 m, and are there¬ 
fore much larger, and proportionately narrower than those of 
our American parasite. The spores of H. psorospermica 
minuta L. Cohn are also much larger and narrower than 
H. wisconsinensis measuring 28 n by 10-11 m- 
The American and the European perches, Perea flavescens 
and Perea fluviatilis , S. respectively are undoubtedly very 
closely related if not identical. It is difficult to believe that 
the urinary bladder of Perea fluviatilis has not been searched 
by some one of the many European workers on protozoan 
parasites. The occurrence of H. wisconsinensis in the 
American perch and its apparent absence in the European 
species is therefore of considerable systematic interest. 
The classification of the species described is as follows: 
Phylum Protozoa 
Class Sporozoa Leuckart 
Sub-Class Neosporidia Schandinn 
Order Cnidosporidia Doflein 
Sub-Order Myxosporidia Biitschli 
Legion Polysporea Doflein 
Family Myxosporidia Thelohan 
Genus Henneguya Thelohan 
Species wisconsinensis n. sp. 
