10 -ON THE CLASSIFICATION OF THE MYXOSPORIDIA, A GROUP 
OF PROTOZOAN PARASITES INFESTING FISHES. 
BY R. R. GURLEY, M. D., 
Assistant, U S. Fish Commission. 
Up to the present time very little attention has been given to the diseases of 
fishes and to their parasites from the standpoint of the effect produced upon the host; 
yet there can be no doubt that a knowledge of such diseases would be of great prac- 
tical value. Anyone who considers the proportions that fish epidemics sometimes 
attain will hardly be inclined to question the utility of searching investigation in this 
direction. Thus, to take a single instance, Prof. Forbes states * that in the epidemic 
of 1884 in Lake Mendota it was estimated that fully 300 tons had died. On August 7 
the Madison Transcript reported that 200 tons of fish had been hauled away by the city 
authorities during the four weeks preceding and that the fishes were still dying. Epi- 
demics of similar extent have been reported in Europe, for several of which (that of the 
barbel certainly, and that of the crayfish probably) the Myxosporidia are responsible. 
The important results in the way of prevention of epidemics among domesticated 
animals and cultivated plants, obtained as the result of scientific investigation, afford 
ground for the hope that similar results may be obtained here. Obviously the first 
step in work of this kind is the collection of facts, especially those bearing upon the 
parasite, its nature, life history, intermediate hosts, enemies, and its connection 
(whether causal or otherwise) with diseases or other morbid processes in its host. 
Such data are a necessary preliminary to preventive or curative measures. 
The present paper and a more extended one now in preparation are intended as 
contributions to the objects indicated. In the latter paper the practical bearings of 
the subject will be fully discussed, and all the data as to epidemics of myxosporidi- 
osis will be given. At present it is desired mainly to discuss the classification of the 
subclass Myxosporidia Biitschli and to record such genera and species as a study of 
the literature and of such material as w r as available has led me to recognize. These 
forms will all be fully described and figured in the second paper. The present only 
includes such true Myxosporidia as have received or appear entitled to receive binomial 
names; and only such synonymy as is needed for their identification. 
Bull. U. S. Fish Com. 1888, vm, p. 482. 
