ROTATORIA OF THE UNITED STATES. 
73 
In the following list those species representing the autnor’s investigations of Lake 
Erie during the summer of 1898 are numbered consecutively; those not observed here 
are not numbered. After each locality is given the name of the investigator who has 
recorded it, followed by numerals showing the year in which the publication took 
place. The exact reference may then be determined by turning to the list of litera- 
ture at the end of the paper, where the authors’ names are arranged alphabetically, 
and the papers of a given author are distinguished by prefixing to each the number 
of the year (in the century) in which it was published. In certain cases species are 
recorded in proceedings of societies as having been exhibited by some member of the 
society; in every such case the citation is given under the name of the member who 
made the exhibit. In some cases I have recorded here for the first time localities other 
than Lake Erie in which I have at some time observed a species; these localities are 
signed with my own initials (H. S. J.). 
The region studied by the author during the summer of 1898 consisted of the 
waters about South Bass Island, especially the waters of the lake along the shore of 
the island. Naturally the waters in the immediate neighborhood of Put-in Bay were 
most carefully examined, since the laboratory was situated on the shore of this bay. 
Many excursions, however, were made to more distant regions. East Harbor, south 
of the island, on the northern shore of Ohio, furnished many of the rotifers. Others 
came from towings made in Lake Erie- at a distance from shore. Two swamps on 
South Bass Island were carefully examined; one lies close to the United States fish- 
hatchery, while the other lies on the east shore of the island, just east of the village 
of Put-in Bay. The latter is referred to in the list as “East Swamp.” The swamp 
near the fisli-liatchery is connected with the lake by a channel about 50 feet long, and 
is situated at such a level that at times water flows from the lake into the swamp, while 
again it flows from the swamp into the lake; therefore, as might be expected, the 
limnetic rotifers of the lake sometimes occur in the swamp, while at other times the 
fauna of the swamp is of the most pronounced stagnant- water type. East Swamp 
has no connection with the lake. 
The proper classification of the Botatoria presents great difficulties. The system 
most in use is that of Hudson and Gosse, as given in their Monograph of the Rotifera. 
This classification is unsatisfactory in many ways, and what I consider a better one 
in many respects has recently been proposed by Lund (’99). After consideration it 
was decided, however, not to introduce this new classification into the present paper, 
as most workers on the group are now better acquainted with the classification given 
by Hudson and Gosse, so that the use of their system will best facilitate reference to 
the list. The sequence of orders, families, and genera adopted is therefore that of 
Hudson and Gosse, in the Monograph of the Rotifera published in 1889, with some 
modifications rendered absolutely necessary by more recent investigations. 
