Diseases of Fishin the Adirondacks 9 
are to be found on all parts of the body. On June 24, 1913, forty-four 
perch were studied with the following distribution of the parasites 
as seen through the skin: head, 38; gills, 5; trunk, 82; tail, 78. On 
August 7, 1913, one perch was taken which had over 30 fully developed 
Clinostoma encysted around the mouth cavity alone. 
Judging from one summer’s study, the number of adult parasites 
in a perch varies from month to month. This seemed to be noticeable 
early in August when a smaller average number of the “ grubs ” was 
found than late in June. Certainly the perch secured in September and 
especially in October were not as extensively infected as those taken 
early in the summer. 
The ponds studied this past summer were selected because previous 
experience led me to believe that the perch were practically free from 
“grubs ” in certain ponds. All of them are located in Franklin County 
and in Townships 19 and 20. Three pairs of ponds were selected as 
follows: West and East Pine Ponds; Copperas and a small mud pond; 
Follensby Clear and a nearby pond called Green Pond. The perch in 
East Pine, Copperas and Follensby Clear Ponds are and have been 
badly infested with Clinostoma for years, while in West Pine, in the 
mud pond near Copperas and in Green Pond, one may catch a fine 
mess of perch nearly all of which will be entirely free from parasites. 
All six of these ponds are practically spring-fed ponds. Copperas, 
Follensby Clear and East Pine each has an outlet. The water varies 
in depth from shoals so shallow that one must pole the boat to large 
areas 30 feet or more in depth. Some of the ponds are almost en- 
tirely free from weeds or lily-pads while others have many aquatic 
plants. The bottoms are muddy, sandy or gravelly. West Pine and 
East Pine Ponds are separated by a ridge some 300 feet wide; a much 
lower ridge of less than 250 feet separates Copperas and the mud-pond 
near it; while a strip of land of about 4oo feet lies between Follensby 
Clear and Green Ponds. No constant physiographic factor was observed 
as belonging either to the ponds where the fish were parasitized or to 
those where they were non-parasitized. (Herons and Kingfishers were 
as frequently seen flying from one as from another). The shallow, 
muddy-bottomed pond near Copperas Pond contrasts strongly with 
the gravelly bottom and clear water in Green Pond, and yet 80 per cent 
to go per cent of the perch taken from each were free from parasites. 
Where does Clinostomum spend the winter? This question cannot 
be definitely answered at this writing. But the fact that perch are 
secured during the winter free from “ grubs” would indicate that they 
do not remain in a passive state in the perch until eaten by some bird 
