B be! 
The carp, Cyprinus carpio L., furnished the largest 
series of returns. In Table V, p. 18, the 37 carp returns are 
divided into five convenient time periods and the migration con- 
stant is calculated for each. In contrast with the similarity 
of these calculated migration constants, the average distance per 
day varies widely, as may be seen in the last column. 
Since the number of returns on other single species of 
fish is insufficient for statistical uses, I have lumped the data 
from all of the basses, crappies, and sunfishes—the so-called 
"Fine fish." It may be seen in Table I that all of these have 
similar calculated rates of migration. These data have been 
arranged in three different time periods in Table VI, p. 19, where 
it may be seen that the calculated migration constants are more 
uniform than the average distances per day. 
To determine whether fishes of different sizes migrate 
at different rates, the 37 returns from carp, which ranged from 
1 to 54 pounds, have been divided, in Table VII, p. 20, into 
four weight classes. The migration constants for these four 
weight classes vary from 0.23 to 0.66 but it is not considered 
that these numbers indicate any real differences in rate of 
movement between carp of different sizes. 
In Table VIII, p. 20, these 37 carp have been divided 
according to streams, and migration constants calculated. The 
data on some of these streams are too fragmentary to be of much 
significance, but the returns from Fox River carp are sufficiently 
complete, and diverge from those of other streams so widely, that 
it seems certain that carp do migrate shorter distances there than 
in other streams. The reason for this lack of extensive migration 
in the Fox River is obvious since it is crossed at many points 
between McHenry and the mouth by dams. These dams are high enough 
to prevent fish going upstream at any time except during very 
high floods, and from going downstream, unless they go through 
the turbines or over the tops of the dams at flood stage. Further- 
more the river was so low throughout 1930 and the years succeeding 
that carp are for the most part restricted to the pools immediately 
above these dams. 
For 15 years the carp of the upper and middle [Illinois 
River have exhibited an unusual abnormality referred to by local 
fishermen as "knothead" carp. We have learned that the knothcad 
abnormality is caused during the carly life of the carp by certain 
pollutional conditions which cxisted in the Illinois River. In 
the winter of 1926-27 when a detailcd study of the knothcad 
abnormality was made in the Illinois River, it was found that 
approximately 90 per cent of the carp from Peoria Lake and points 
upstream, showed abnormality in grcatcr or smaller degrees. 
