ECOLOGICAL SUCCESS!* >N . 



133 



found there, though the passage between the outlet and pond I 

 had been open two \ears before. \Yhy have tin- ti-h vacated or 

 avoided the outlet? One can only suggest a behavior reaction 

 is the cause. 



TABLE I. 



I >IMKII'.I I I' > v - i>K THE FlMI. 



The letter-; and number- at tin- In -ad- il the column- reier t. > tin- vai i< ni" i-' ilated 

 part i- and. i-xo-ptini; <> which n-ii-i- tn tin- "iitl'-t. may l>e Incated an Map 



II. Tin- la-t column indi. at'-- tin- occurrence <>t fish in the older ponds <>t the 

 -'ri'--. uhiili ari- iii.t imjud "H thi- map; the nuiii i i the number of 



th<- p.iifl in whirh the fi-h \\i-n- lOund. ' indicate" an incmnplete identiticatinn. 



'I'lit- IM-I-I-II i- di-iribinril ill a -till nmn- [n-culiai way. Ii is 

 I'liiind in I'-'iiil- i and 5i.bin ;/"/ in tin- (.mid i, r in r.nnl- 5</ 

 and .V-. 5-.' ainl 5 ! \\itli tin- outlet until [907 



but 5- ha- |robabl\ been separated -imv I s .^ I , \\heii the I. S. \ 

 M . S. \\ \\ \\.i- built . I ha\ e no -\ ideiiee I h.it .1 >luire \\.i- CVCf 

 tuaintaineil under llii- railio.ul in I'oiid 5. The perrh i- then 

 di-tributed in -u h a \\.i\ .1- to necessitate the eonclu-ioii, cither 

 that it \\.i- artitieJ.tlh int roduei-d or that il \\.i- once in the 

 outlet and in I'ond 5-.' and .V'. because ihe-e make the only 

 pa-^agi- to I'ond ,v u here it uo\v oi-cui 



The chub Mirker i> in all the pond- up to ~ : . excepting 5; 

 and ~ii. The passage to. from, and through 1'ond 5..'. and oilier 

 point- \\liere the rhub -ueker occurs, \\a- open until 11)07 .mil 

 the erueial rolleetin^ \\a~- done in [908. Il \\ill be noted ihat 



