ON THE I;i;il\\!"K < ! TUBICOLOUS \N\KI.IDS. 85 



or fifteen days after the aquaria had been rotated, the conditioti- 

 .in- ,i- follow-,: Five specimens now face the light, while three 

 I". u i the opposite direction. But of the five now facing the light 

 three were so placed in the readjustment made by the rotating. 

 or n Aer-ing of the tank, so that only two ha\e actually shown 

 a po--il>le light reaction. The three specimens \\hich had been 

 turned auav from the window by this reversal had not sho\\ n 

 i li' sliijiu-i response. 



At i hi- i ime the acjuaria were again reversed, so that they came 

 back to the original positions. It should be noted that in the 

 control i. ink there had been no change induced by the re\er-al 

 ol tin pi -i i ion, the specimens all remaining as before. 



Another a-|>ect of behavior may be stated in thi- connection. 

 n.imel\ . an actual downward curve of several specimen-. It was 

 on in-t notice thought that possibly this might be due to the 

 iin inn -in water, which happened to be in the region ot one such 

 llouever. it was later observed that other specimens quite 

 remoii- -houi-d the same thing, and on comparing similar con- 

 dition- in the exhibition aquaria it was found to have it- counter- 

 part there, 1 1' nee it may be regarded as only another cxpre--ii.n 

 \ the individuality of behavior which is more or less e\ident 



iimler all i "minions. 



The e\pi liments \\ith these special aquaria \\eiv continued to 

 M Mch J5, having thus been under operation for about ten weeks 

 i JannaiA i ;> to March 25), and have been in the present pi .-it ion 

 loi e\aitl\ one month. During this time there ha\e been inci- 

 dental -hillings on the part of various specimens, a bending this 

 \\a\ or that from time to time, but only to be re\-r-ed later, or 

 counterbalanced by opposite reactions of adjacent s|iecinien-. 

 The-e ha\ e been noted from lime to time during the o >ur-e of all 

 the experiment-, and are not to be considered as orienting re- 

 action-, but rather expressions of the individuality ot behasior 

 charactei i-t ic. a- I believe, of .ill grades ol animal behavior. 

 Tlu-\ correspond to what Jennings ha- de-ignated as trial rc- 

 (udons; and in the present instances probably relate to fo.>d- 

 seekinj or n-piration. These statements refer directly to 

 condition- in the darkened aquarium; but they are quite as 

 applicable to those of the control aquarium, and indeed, the 



