PAGE 



Entomostraca 221 



Branchiopoda 222 



Cladocera 223 



Cladocera and Hydrographic Fluctuations (Table) 223 



Discussion of Species 225 



Tabular statistical data: 



Bosmina and hydrographic fluctuations . r- 228 



Seasonal distribution of Chydorus. Average number per m. 3 . . . 235 



Effect of temperature on numbers of Chydorus 238 



A typical pulse of Daphnia cucullata 242 



Diaphanosoma population, with data of temperature and river 



level 248 



Moina and hydrographic changes 254 



Ostracoda 257 



Discussion of Species 258' 



Copepoda 258 



Copepoda and Hydrographic Changes (Table) 260 



Discussion of Species 261 



Cyclops viridis var. insectus and Hydrographic Changes (Table). . 274, 275 



Relative numbers of adult, young, and larval Cyclopidae (Table). . 278 



Amphipoda 283 



Arachnida 283 



Acarina 283 



Tardigrada 284 



Hexapoda 284 



Ephemerida 285 



Hemiptera 285 



Diptera 285 



Mollusca 287 



Gastropoda ' 287 



Lamellibranchiata 287 



Bryozoa 288 



Discussion of Species 288 



The Periodicity in the Multiplication of .the Organisms of the Plankton. . . 291-311 



Comparison of Plankton Pulses and Lunar Cycle (Table) 296-299 



Gaseous Contents of Pond Water (Table) 306 



Relation of Pulses of Chlorophyll-bearing Organisms to Lunar Cycle 



(Table) 308 



General Considerations on Seasonal Changes 312 



Lake versus River Plankton 312 



Organisms per Cubic Meter in Plankton of Illinois River in 1898 (Table) . . 314-340 



Bibliography 341-354 



Explanation of Plates 355 



Diagrams of Seasonal Distribution 356360 



Errata and Addenda. . 361 



