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Attectedibysenvironmentall factors... seers ees ee ee ieee ie tise ei 510 
Approximation in time of pulses at different stations.............. 510 
Normal regimen in our waters one of recurrent pulses of varying am- 
plitudes 
JORG HOOND DOU DOKI COAT SAE aE nberican fecal CHO ROAE OCH 51 
Source and maintenance of potamoplankton...................2-02+2: 511 
Broblemistated-tr.% reterelorc (ict isles «'s <raie aie sis’ siocanyevate Setetererae cate siete cies syaseie Sil 
Relationvofsseepayeuwatershn seca, sane cco co csiasnsaraarstainreets sateore eae 512 
Nelationsob tribitaryeastheamss 4.20011 4... geek aemecrees cates oanicrsarcec 513 
EXAMI ApONeOHG@ iver CheeRs janie slo) occ) < iselrse eece serie eee eee ie eee 514 
Gollectionsiandiomethod ss sith oie cise tociciesrolistiecs © e cesmoeeteisiers ae 515 
Gonstituentsjof @Oniver Creek plankton... oe ecececsn connec s seme 516 
Comparison with plankton of river. occ.2.. cesccecs caceeees acer 517 
Quiver Creek a diluent of channel plankton......... ........... 518 
Relative numbers of species in tributaries and river.............. 519 
Ghemicalkconditions:-Aec.s nie ctais siete sacs’ 1c0e.z/scn.e) aye Syelere, « eps)sie.seyasmarers 520 
EXAMIBA OD) Oly SPOONU RIVED ci ccsc ete cyelcioesc/siet ie wc winters aver els mies teres 521 
Comparison of chemical conditions in Spoon ind Illinois rivers... 521 
Resources of Spoon River adequate for large plankton......... 522 
Lack of time for breeding a cause of barrenness..............-. 52 
Comparison of quantitative plankton production in Spoon and 
MMiNOIShniVEr Sarasin Me eeioe Tokers saree keh eee a Tastevercimiee ere’ 523 
Errors resulting from leakage and silt.......................- 523 
Statistics of production by monthly averages of all collections.. 525 
IRATIOIOH PTOGUCHOME ies cisorce emo eye oletete oie nicleieemiclere ela isigicyeic e e}=rs 526 
Comparison of statistics of coincident catches................. 527 
Cause of periods of relatively larger production in Spoon River. 528 
Quantitative effect of access of tributary water formulated....... 529 
Qualitative analysis of plankton of Spoon and Illinois rivers...... 530 
Contrastuinitotalepopulatione an. ..ss loess cecmioe sietclefeisileleet= 531 
Relative development of different groups..................... 531 
Pl ceceetetey Vetch stotte SBT Tt cPafatollcsc-arie cletelanaiare chelsivisieleisysue eleivia etaiaisretei 531 
IDMEKO TW na56 no00 6AGd aaa 4605 000m Dood Good ugad CONEObOD cooaaaS 532 
IAD A5om, cade 6soudsadounoe bdadadne Uesecsc. sogDandO.cdae 533 
MAGN Royal) hs 5 ddiacicd onda Sa04 GuacnOno-conD moe pocodacoos DS 533 
Wiater-bloomlol SPOOMURIVER. .cyarcclaeniieceeesusaciclen tee cere 533 
Iowa SOITEY Sab 4 an atiooe Choc Obb0.0bc sObnuSes dose Goan coo qoeu aK 534 
IRCTALKO Ean 4 Bb Son SOOO BEERIDAIG HO OOND DUT, Jobers oe OOUO COBNbOCS 534 
JOA COMI, sca chnaasoon pono COD CoUanoeD Gooh DOUA ogODBHDGO 536 
INNA AVES 5 ogee Saboan sopo MOU GNoUNGo GScbwo on bode COonE 536 
Comparison of total number of species.....................+.- 537 
Com panisonromscasOnale TOME > =-eteraete spereret sl aleletaialsielisteleteloleieleteels 537 
Contrastsiimeautumnall plankton jor cece cere eect sieice 538 
Applicability of conclusions to other streams...................-- 539 
Effect of tributaries upon channel plankton......................- 539 
Relation of backwaters to channel plankton.................-.+-.5-- 540 
(Copnalessisy OUUNS joys oo qaeaoangoconode coon dosodnocongbccnon 540 
Impounding action Offood-plain. .|..1. 1.) eres lees so cee s ele oe 541 
ATMO UIMHO Tm OUMG CAhwaterye wapyesde tale ete tocate ote cleici=tesisietalevalel ola cleliete «te 541 
Duration Gl WoIpPOUMGiM es we esiels seis ieteleicieel sie reiaiata claetvieleieie cies) 542 
