Pearse—The Parasites of Lake Fishes. 
185 
pickerel 3.1, speckled bullhead 2.9, white bass 2.9, channel cat 
2.7, tadpole cat 2.5, mongrel buffalo 2, hackleback sturgeon 1.8, 
sauger 1.7, wall-eyed pike 1.6, pumpkinseed 1.3, white crappie 1, 
yellow perch 0.9, shiner (Notropis heterodon) 0.8, short-headed 
redhorse 0.7, long-billed gar 0.6, largemouth black bass 0.5, bluegill 
0.5, mooneye 0.4, white-nosed sucker 0.4, black crappie 0.4, Johnny 
darter 0.2, shiner (Notropis atherinoides) 0.2, log perch 0.2, carp 
0.1, shiners (Notropis jejunus and N. hudsonius) 0.1, pirate perch 
+, gizzard shad 0, lamprey 0. 
Green Lake : Pumpkinseed 29.7, blunt-nosed minnow 22.5, 
sucker 21.4, rock bass 8.9, bluegill 4.2, yellow bullhead 2.5, small- 
mouth black bass 2.5, cisco 2.4, carp 2, speckled bullhead 1.9, top 
minnow 1.1, largemouth black bass 0.8, yellow perch 0.4, pickerel 
0.4, Johnny darter 0.1, shiner (Notropis atherinoides) 0. 
Lake Michigan: Whitefish 31.1, smallmouth black bass 28.9, 
blackfin 27.8, pumpkinseed 18.9, carp 15, rock bass 12.6, lake 
trout 9.2, speckled bullhead 6.5, chub 5.8, mud puppy 5, black bull¬ 
head 4.1, bloater (Leucichthys harengus) 3.9, lota 3.9, bloater 
(Leucichthys hoyi) 2, log perch 1.5, pickerel 1.4, cottid 1.3, sucker 
1.2, top minnow 1, Iowa darter 0.9, long-nosed sucker 0.8, Johnny 
darter 0.8, yellow perch 0.5, bream shiners (Notropis atherin¬ 
oides and N. hudsonius) +, blunt-nosed minnow 0, yellow bull¬ 
head 0. 
It would not be proper to add the average infections in different 
lakes in order to compare infection in different species of fishes, 
for the total infection in different lakes varies greatly. Each spe¬ 
cies should be given a rating which will compare it with all others 
in each lake. The writer has therefore used the following formula 
in order to give to each fish a relative percentage (P). 
p=100—I^XR 
N is the number of fishes examined in the lake; B, the rank of 
the particular species of fish in the lake according to its average 
infection. For example twelve species were examined in Lake 
Geneva (3^). The largemouth black bass ranks sixth (^^X6). 
For this species P=100—i^X6—50. Using this method for each 
lake and averaging the relative percentages for all species of fishes 
that occurred in two or more lakes, the fishes rank in the follow¬ 
ing order: dogfish 90, smallmouth black bass 78, white bass 78, 
