400 BULLETIN OF THE BUREAU OF FISHERIES. 
Table 23 . — Composition of the plankton of the Mississippi River, and Lakes Pepin, Keokuk, and St. Crpix — 
Continued. 
Rotatoria: 
Asplanchna amphora H 
priodonta G 
Synchgeta stylata Wierz 
Triarthra longiseta E 
Polyarthra platyptera E. v. euryptera W 
Notops brachionus spinosus R 
Rattulus rattus M 
pusillus L 
stylatus G 
Diurelia stylata E 
Dinocharis paupera E 
Euchianis dilatata E 
Cathypnaluna O. F. M 
Monostyla cornuta O.F.M 
lunaris E 
bulla G 
Brachionus angularis G 
angularis caudatus B & D 
pala f . amphiceros E 
pala E 
pala E. <? 
pala v. dorcas G 
pala v. dorcas f. spinosus W 
bakeri O. F. M. v. brevispinus E 
bakeri O. F. M. v. cluniorbicularis S . 
bakeri O. F. M. v. entzii F 
urceolaris O. F. M 
budapestinensis v. D 
Noteus militaris E 
Schizocerca diversicomis v. D 
Anuraea cochlearis G 
cochlearis v. tecta g 
Anuraeopsis hypelasma G 
Pedalion mirum H 
Cladocera: 
Sida crystallina O.F.M 
Diaphanosoma leuchtenbergianum F 
Daphnia pulex v. pulicaria F. 
retrocurva F 
arcuata F 
longispina O. F. M 
Scapholeberis mucronata O.F.M 
Moina rectirostris L 
brachiata J 
macrocopa S 
Bosmina longirostris O. F. M 
Alona sp 
Leydigia quadrangularis L 
DunhevecBa setigera B 
Leptodora kindtii Lill 
Copepoda (Cyclops and Diaptomus) 
Nauplii 
Corethra sp 
Chironomus larvas 
Hydra sp 
Glochidium 
Mayflies (larvae) 
Mosquito larvae 
Detritus 
Mississippi River. 
Lake 
Pepin, 
Aug. 
15 to 
Sept. 
10. 
Lake Keokuk. 
Lower part, be- 
tween Rock 
Island Rapids 
and Burling- 
ton. 
Upper part, be- 
tween Reads 
Landing and 
Rock Island 
Rapids. 
Above 
Lake 
Pepin. 
Upper 
part, 
July. 
Lower 
part, 
July. 
July. 
Au- 
gust. 
July. 
temper. 
O 
o 
O 
8 
© 
6 
6 
6 
6 
! 
© 
© 
o 
O 
O 
o 
Q 
o 
© 
o 
© 
© 
8 
o 
o 
o 
8 
6 
8 
8 
6 
6 
6 
6 
o 
0 
8 
8 
6 
6 
6 
6 
8 
© 
8 
© 
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o 
o 
o 
o 
© 
8 
Cl 
- 
Cl 
Cl 
8 
3 
9 
6 
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6 
6 
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6 
6 
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6 
6 
6 
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8 
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K1J 
8 
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6 
6 
6 
8 
0 
o 
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8 
8 
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6 
6 
6 
6 . 
© 
© 
6 
6 
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6 
6 
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6 
6 
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© 
§ 
8 
8 
© 
1 
o 
o 
o 
o 
o 
© 
8 
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6 
o 
6 
§ 
8 
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6 
6 
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• 
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o 
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Lake 
St. 
Croix, 
Sep- 
tem- 
ber. 
O 
O 
6 
o 
o 
o 
o 
The plankton collected in different parts of the river, in the lakes, and in the 
tributaries can be characterized as very uniform. The samples taken from different 
localities differ mainly in the amounts of plankton they contain, or in variations 
in the abundance of, or even in the absence of several forms; but there is not a 
