72 
BULLETIN OF THE UNITED STATES FISH COMMISSION. 
2. New species should not be described as a result of the discovery of some 
hitherto unmentioned anatomical detail in an otherwise known species. 
3. Great care should be exercised not to describe as new species mere variations 
of an old species. 
4. If any doubt can possibly exist, the figures and descriptions should be 
submitted, before publishing, to some expert who has all the literature at hand. 
5. A description of a new species should be accompanied by a detailed comparison 
with any very closely related species that may exist, to show wherein this one differs 
and why it is considered new. 
6. Every description of a new species should be accompanied by a good figure or 
figures. 
For the two cases in which it has seemed necessary to describe certain forms as 
new in the present paper, an attempt has been made to fulfill these conditions. 
The subjoined list contains not only the species found by the author in Lake Erie, 
in the region of South Bass Island in the summer of 1898, but also, so far as known to 
the writer, all the species that have been found in the United States, together with the 
localities from which each species has been recorded. An attempt has been /made to 
make this list as complete as possible, but the references to the Rotatoria are exceed- 
ingly scattered, so that I can not hope that none have been overlooked. Nevertheless 
it is believed that the omitted references are v.ery few. 
A brief review of the history of the study of the Rotatoria in this country may be 
of interest in this connection. The first recorded observation of any member of the 
group in America seems to be that of Bose (1802), who observed some rotifer belonging 
to the Philodinidce in Carolina. Ehrenberg in his great work (’38) held Bose’s animal 
to have been Rotifer vulgaris , while in a later paper (Ehrenberg, ’43) he considers it to 
have been probably Callidina rediviva Ehr. 
The next notice of American Rotatoria that I have been able to find is that by 
Ehrenberg (’43). He lists a few rotifers observed by him in material sent to him from 
this country by various men of science. 
In 1S55 Bailey (’55) described Limnias annulatus Bailey. 
Schmarda (’59) in his trip around the world, 1853 to 1857, observed two rotifers 
“in brackish water near New Orleans.” 
From this time on, up to 1879, little notice of the Rotifera is to be found in American 
journals, save a few notes by Leidy (’51, ’57, ’74, and ’74^) and one by Peirce (’75), in 
the Proceedings of the Academy of Natural Sciences of Philadelphia. 
In 1879 the late Dr. D. S. Kellicott published his first note on the Rotifera, a 
description of Notliolca longispina Kellicott. This was followed by many other papers 
on the group, up to the year before the death of this author iu 1898. The decade from 
1880 to 1890 was marked by numerous brief papers and notes on the group, by Kelli- 
cott, Herrick, Leidy, Attwood, Yorce, Forbes, Foulke, Stokes, Up de Graff, and others. 
The first formal list of American species was that of Herrick (’85) of rotifers found in 
Ohio and Minnesota, followed with one by Kellicott (’88) of rotifers found at Corunna, 
Micti. 
In the decade now coming to an end, work on the group has been much increased, 
especially in connection with the founding of fresh- water biological stations. Extended 
local lists of species have been published by Turner (’92), the present writer (’94 and 
’96), Kellicott (’96 and ’97), and Hempel (’98). 
