8 
From these color drawings were made, under the constant 
supervision of Mr. Large, accurate in detail, and true to life 
in color, form, and attitude. Sixteen such plates were fin- 
ished during the season. <A reproduction of these exquisite 
drawings by a method in keeping with their quality will call 
for an appropriation of some thousands of dollars, but will 
give us a more finished series of plates of American fresh- 
water fishes than has yet been published. It is my pur- 
pose to illustrate every species by such a plate, with black 
and white figures additional to exhibit technical characters. 
STUDY OF THE PLANKTON. 
Our systematic study of the minute plant and animal life 
of the water (commonly called the plankton) was quite fully 
described in my last report. This work was continued at 
Havana until interrupted by the removal of the Biological Sta- 
tion to Meredosia in April, 1899. Since that time field work 
on the plankton has been limited substantially to ordinary 
collections with a tow-net from the river at Meredosia and in 
Meredosia Bay and to a series of quantitative collections made 
during a trip of the steamer of the Illinois Fish Commission 
from the mouth of the river to Hennepin in May, 1899. This 
series was intended to give us the materials for a knowledge 
of the distribution of the plankton in the course of the river 
at the time. By means of a submerged pipe which delivered 
water to the net as the boat progressed, collections were made 
with ten-mile intervals throughout the trip. 
Regular plankton work was begun at the Biological 
Station in June, 1894, and was kept up with no importaut 
break to the time of suspension above mentioned, that is, for 
nearly five years. The vast accumulation of material thus 
obtained is now undergoing examination by Dr. Kofoid and 
by assistants under his immediate direction, in the expecta- 
tion that results in form for publication may be reached early 
next year. This is by far the largest and most valuable body 
of work on the minute plant and animal life of a river system 
which has ever been brought together, and the publication of 
our full reports upon this subject will contribute in a notable 
