Variati 
xii 
ons in plankton, enumerative method.................- 
Plankton in cross-section of river below Spoon River. ........ 
Effect of Spoon River and Quiver Lake.................+.200:- 
General summary of data of distribution of plankton................ 
Validity of 
application of plankton method to streams. ............ 
Plankton production in Illinois River channeél.............-...-.0++- 
In 1894... 
Collections, statistics,and hydrographic conditions............... 
Seasonal 
GisteibutiOwis gs acre cere cae ete Metre ces oti eke lee hetepetanees 
Coniparisons’ and summanry,-nc asec eeeeiaa eases sisererise 
In 1895.... 
Collections, statistics, and hydrographic conditions..,...........- 
Extermination of plankton under the ice in February............ 
‘Apparent.absencesofsyerually pulser at aeereeieseliteee tei rer 
Stagnation \pul seni na |une sesame ie mie enna icial-restars 
Phenomenon of recurrent pulses in production................... 
Discussion of the August-December pulses............--.0+2000 
Comparisons/and,summanyer ce swe eee car etion secrete see ei 
Collections, statistics, and hydrographic conditions.............- 
The winter plank tony renee eres ere eas ete eta tetera aie oe ee 
The vernalpulsé: Sq :trsaterca cuore ciate trsietetetre mci roia ater Posatehe ces ielete talerel 
Discussion of May-August pulses.................0.0022ee seen 
Autumnal planktom:2 <a. ac seis close sete tes ie ineraters re cite cis rsyensteverer= = 
Comparisons andismmamanyyerei-y-ioiel-dere siete eecieralolersteeieetsier setter ers stele 
In 1897.... 
Collections, statistics, and hydrographic conditions.............. 
Blankton of first halfay Garni 1-2)5)-1rs eiectaeioie ore teiereietniare sie ean 
Discussion of July-December pulses.................-..0+2- 00+ 
Comparisons and) SuMMALy/< eye lates olm ols oe =)=\elelere) olalela ne eelate l= eel wel 
In 1808.... 
Collections, statistics, and hydrographic conditions............... 
Discussion of the January—March pulses.................2.---+-- 
Mhe vernal) pulses AjpmilMictiy eter metspeenstetater tetera te keretter= teres] ener stor ete 
Description and environmental conditions...... ..........+++- 
Factors causing the unusual vernal pulse...................... 
Effect of foodionavernalipulsecjnierrt- settee eit steecienei aaa 
Discussion of June-December pulses...............-.+---+.00-- 
Comiparisons|and sSumimatyenye ty tele es diets slate loietele siete tainin araleneiateter = = 
In 1899.... 
Statistics and hydrographic conditions............-...+sseeee0e- 
Discussion of January-March pulses.......... 2... .eeseeeeee eee « 
Conclusions and (comparisons: yates ese eieteisleteilel sterile viene’ = 
Comparisons w 
Spoon River, 
ith tributaries and backwaters.................22-00-- 
Station Mey coe aieckre ects owe eestetetaianeroeste oie nveyetes revels ateteencte 
Environmental conditions, «sac nceees es een eoieeencenecie estes 
Collections 
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