110 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
these infusoria appear and disappear in the culture jar about as the lower algm do. 
The power of movement, regulated in the simple manner above described, is correlated 
with the fact that, unlike plants, they live upon solid food (bacteria) and are therefore 
more likely to get this food if they can move about here and there. But the bacteria 
must be abundant in any case, for the Paramecin have no power of searching for them, 
or of choosing them rather than any other substance. 
In future work it is hoped to determine how far the results gained on Parame- 
cium are applicable to the Protozoa as a class, as well as to extend these researches 
to higher groups, building upon the foundation obtained by a study of these lowest 
organisms. In this way it is hoped that the laws which govern the movements and 
migrations of animals, the causes of their appearance and disappearance at certain 
places or under given conditions, and in fact much of their relations to the conditions 
surrounding them in the lake, may in time be made out. It is the belief of the writer 
that this is the most direct and certain way of unraveling the complicated network of 
relations which make up the life bf the lake. 
In addition to the study of the reactions of the animals above summarized, some 
faunistic work was carried on. An examination was made of the waters on and about 
South Bass Island, with the purpose of determining the abundance and general char- 
acter of the Protozoan fauna. The swampy waters of this region were found to 
swarm with Protozoa of all sorts, ottering unlimited supplies of material for work on 
the group in experimental or other lines. Unfortunately, the literature was not at 
hand for complete identification of all the species observed, so that critical systematic 
work, of the sort done on the Botatoria, could not be carried on for the Protozoa. 
Only those could be positively identified that agreed completely with species described 
in the standard works on the Protozoa — Leidy’s Rhizopoda, Kent’s Manual of the 
Infusoria , Biitschli’s Protozoen , Eyferth’s Pie einfaehsten Lebensformen des Thier-und 
Pflanzenreiches , Bloch man n's Pie milcroslcopiscUe Thierwelt des Siiss wassers , Pritchard’s 
Infusoria , Ehrenberg’s Pie Infusionsthierchen als rolkommene Organismen , etc. 
The following list therefore contains the names of such species only as could be fully 
identified, and comprises thus but a fraction of the Protozoan fauna of the region. It 
is given in order to show something of the character of the abundant Protozoan fauna 
of these waters, as well as to point out forms that are of especial interest as favorable 
objects for investigation. Especial attention was paid to forms which from their size, 
or from the possibility of securing them in great abundance, promise to be particularly 
favorable for experimental work. 
