ECOLOGICAL -U< CE--ION. IQ 



place rapidly. In tin- exi-ting streams the slope of bed dit< 

 within a ^ivcn stream and with respect to the different -treams. 

 The difference- do not appear to be of importance in determining 

 the relation- of the ti-h pre-ent to a stream as a whole. Ac- 

 cordingly, we -hall not consider the effect of rejuvenation in the 

 di-cn--ii in- 1< 'Hi \\ ii 



111. I'K! 51 N I HI!'. IUIA. 1 



I t.tia of the kind upon which thi- paper i- ba-cd are doiibtK us 

 familiar to .ill collr. tor- of ti-h. l ; rom our point of view the 

 presence or absence of is nol "t particular impor- 



tance, but \\e arc concerned with the arrangement of li-h in the 

 -tream- and it- causes, Such causes cannot be di-cu--ed here 

 because th-\- -hould be -mdicd experimentally. A- \et \\e ha\e 

 ii( .t been able to do t hi-. 



2 -ho\\- the -tie.un- and Table I. the distribution ol the 



li-h in the-e streams. 



I . .' ' ! I . 



\\V note that the li-h honied of the -malle-t Stream 



( ,1, I'M... .Is b. long to tin- sam< e at the hea<l- 



r 



D 



B 



L. source; J :n..nth: < 



,,i ITI.-I..II; D, I 'liiiiin- in T.ilil.- 1 1. 



.!!! ' ll | '.II ! - ! ! -111 \vllli ll ' 



Waters Of the lar-et -tream-. The red-bellied dace, \\heil pn-M-iH , 

 i- not foil nil SO tar up-lre.im a- the horned da. . I he r -d- bellied 

 dace i- ab-eiit from ('oimt\ Line ('reek. Since all the li-h in 

 all the -tream- niu-t ha\e eiiter.-d from Lake Michigan, one i- 



I In- ti-h nl C.nimy I. in.- < reek : tln-ir .in.iiiu'-ni'-iH -in.- 



n, .in tiini- t.. tiiiu- l.i-nvi-rn [907 .mil i';i". I 1"- .iM.mK<-inriH ..I tin- ti-h a- -li..\\n 

 l.v tin- III.MI ,.i tin- -tn-.mi \\.i- about t!:.- same thruuKh"iit tin- pt-rii..l- ..i -tinly. 

 ami Tat.li- I.. I-M-I-JU for the drought 1 ln'i-nll.vii..n-; frmii tin- it her -in-.uiis 



\\rii-m.ulrintlu--iimiiu-r ami autumn "i" loop, partly with th- : Mi. S. 



1- Mil. li -1.1.111.1. ..I tin- l-i'-M MII-, -urn ol Natural Hi-t.'iy. 



