OX THE BEHAVIOR OF TUBICOLOUS ANNELIDS. 83 



The most interest attaching to this experiment is the behavior 

 of the specimens suspended. For several days both remained 

 hanging downward. Finally one began to curve, and direct 1\ 

 by a graduated process assumed the aspects shown in the dia- 

 gram figures A, B, C and D. In the entire course of the exprri- 

 incnt ilx-re was not the slightest indication of light response, 

 nor indeed was there more of a geotropic character. The final 

 altitude was that indicated in D. 



The nher suspended specimen attached itself to the side of 

 thr M\( rtlou tube, and has continued head down, without appre- 

 eiable change of aspect, the tube remaining almost perfectly 

 -iraii;lii from first to last. Both specimens seemed equally at 

 , both equally active; but the one passed through the series 

 dl tubular i "iitortions, the other remained absolutely indifferent. 

 lin ideutally it may be remarked that specimens are often found 

 in nature attached to the under surface of bottom of boat- or 

 other -ubstrata, much like barnacles or other sessile organism-; 

 and hence it mu-t be admitted that there is nothing especially 

 unusual or unnatural in such an attitude. That the beha\ ior 

 of i he one difYered from that of the other is not more str.r 

 ill. in that differences likewise appear between others. 



Sf>f< i<il Aquaria. The second series of experiments were con- 

 durt. -d in t\\o special aquaria, mentioned above, and were 

 piompted by two considerations First, the apparently negative 

 ehaiaet. r of the experiments began and carried forward in the 

 lar^e ai|iiaria. It had seemed as if one should have more prompt 

 and eoii\ in. ing results than appeared in the account just given. 

 "v . ou.lly. it was desirable to have aquaria of a size and adjti-t- 

 meiit \\hieh made possible ready and effective control at all 

 time-, \\ith such variation of tests as seemed desirable, lieu.-.- 

 the-e -mailer aquaria already described. They were set in a 

 room \\ho-e light and temperature were under easy control, and 

 \\.re t hem-elves of a size which enabled one to shift the position 

 at anv time it might seem desirable. It occurred to me that 

 po ibl\ the fact that in the first series the light had been ditfu-e 

 rather than direct might have resulted in thr -omeuhai ne^ati\e 

 beha\ior already noted. Again, it seemed de-irable to be able 

 ID rontrol both the direction and inu-n-ity of the li^ht Ac- 



