402 THE AMERICAN NA TURALIST. [VoL. XXXII. 
Anabeena, and Clathrocystis are of frequent occurrence. The 
plankton is remarkable alike for the large number of individuals 
and of species it contains, while in volume per cubic meter it, 
at times, exceeds almost all published records. The fauna, as 
well as the flora, is conspicuous for its abundance and variety. 
Although no efforts have been made to accumulate complete 
faunal lists, over one hundred species of Protozoa have been 
recorded, as well as a like number of Rotifera. Spoon River 
has long been noted for the abundance, variety, and size of its 
Unionidz, thirty species of which are known to occur in the 
vicinity of Havana; there are in addition forty-five other species 
of aquatic Mollusca, largely univalves. Through the efforts of 
Professor Smith over thirty species of Oligochata have been 
found, including a number of new and interesting forms. 
Aquatic insects abound, over three hundred and fifty species 
being known to occur in the vicinity. An interesting feature 
of the richness of the fauna is the occurrence of certain 
zodlogical rarities whose range, as hitherto known in this 
continent at least, has been limited; as, for example, Urnatella 
and Lophopus among the Bryozoa, and Trochosphzera among 
the Rotifera. 
The essential objects and general methods of the [Illinois 
station are best expressed by its director, Professor Forbes, in 
his last biennial report. 
It is the general, comprehensive object of our biological station to study 
the forms of life, both animal and vegetable, in all of their stages, of a great 
river system, as represented in carefully selected typical localities. This 
study must include their distinguishing characters, their classification and 
variations, their local and general distribution and abundance, their behavior, 
characteristics, and life histories, their mutual relationships and interactions 
as living associates, and the interactions likewise between them and the 
inanimate forms of matter and of energy in the midst of which they live. 
We are, in short, to do what is possible to us to unravel and to elucidate in 
general and in detail the system of aquatic life in a considerable district of 
interior North America. 
So vast a subject must of course be intelligently divided and studied part 
by part, in some systematic order, to avoid a dissipation of effort and to 
insure the speedy attainment of some definite and tangible results. Its most 
obvious divisions are the systematic, the biographical, and the cecological; 
