184 Wisconsin Academy of Sciences, Arts, and Letters. 
The lake in which there was the least infection by parasites 
(Mendota) had the largest number of fishes per unit of area 
(Pearse, 1921, p. 24), the most abundant food supply, the greatest 
degree of stagnation in the deeper water during summer. Table 
4 shows, however, that this lake had the second largest number of 
species of parasites which showed the largest number of highest 
infection averages; and that it was excelled in this only by Lake 
Pepin, which had nearly twice as many species of fishes, the 
scantiest food supply, and the greatest parasitic infection. Taking 
the number of species of parasites that showed the highest average 
infections as a criterion, the lakes rank in the following order: 
Pepin, Mendota, Michigan, Green, Geneva. This order indicates 
that there is a direct relation between variety of habitat and amount 
of infection. 
Taking the total number of species of fish parasites present as 
a criterion the lakes rank in the following order: Pepin 70, Michi¬ 
gan 60, Mendota and Green 44, Geneva 35. This indicates that 
variety of habitat is correlated with a large number of species of 
parasites (and fishes) as well as a large amount of infection. In 
other words the lake with the largest variety of habitats has the 
greatest variety of fishes and parasites. 
Arranged in order of average infection the fishes in each of 
the five lakes in which extensive observations were made rank as 
follows: 
Lake Geneva: Kock bass 9.4, pumpkinseed 5.0, smallmouth 
black bass 4.0, sucker 2.2, cisco 1.0, largemouth black bass 0.8, wall¬ 
eyed pike 0.6, pickerel 0.5, bluegill 0.5, perch 0.5, brook trout 0, 
shiner (Notropis hudsonius) 0. 
Lake Mendota: White bass 13.2, wall-eyed pike 12.7, dog¬ 
fish 8.3, smallmouth black bass 6.6, sucker 4,0, long-billed gar 3.8, 
tadpole cat 2.8, pumpkinseed 2.6, speckled bullhead 2.4, largemouth 
black bass 2.4, Johnny darter 2.0, bluegill 1.6, perch 1.4, yellow 
bullhead 1.3, rock bass 1.1, pickerel 1.1, cisco 0.8, black crappie 
0.7, top minnow 0.3, shiner (Notropis heterodon) 0.2, silversides 
0.1, carp 0.1, blunt-nosed minnow +, bream 0, buffalo 0, miller’s 
thumb 0. 
Lake Pepin: Mud cat 462, lake carp 116.6, eel 40, dogfish 
37, spoonbill 19, smallmouth buffalo 17, yellow bass 16, quillback 
13.2, river carp 5, sucker 4.7, black bullhead 3.7, skipjack 3.3, 
