OX Till hi IIAVIOR OF TUBlM'i.nrs ANNELIDS. 7<) 



, were employed for such experiments as called for a critical 

 control of light, etc. Of the large aquaria two were in a room 

 with north exposure, and hence with diffu-e light. Inn al\\a\- 

 adequaie for ordinary observation and experiment: while tin- 

 other was in a room with direct south exposure, In-mv with -un- 

 liyht ot almost any degree of intensity, modified by -hade- 01 

 screens. I In- iwo smaller aquaria \\eiv in a special room, the 

 light ol uhich was under easy control, and tin- aquaria them-cbe- 

 ea-il\ adjusted to any desired condition. a- to amount and direc- 

 iin o| li-ht. t-ic. A still further point i- \\orthy of notice At 

 all time- I had In-i- access to the latxe exhibition aquari.i, win-re 

 laro- number- ol these specimens \\eiv living under condition- 

 as iit-.irlv natural a> the long experience and painstaking -kill of 

 tho-e in <h.iro ha\'e been able to devise. 1 -hall ha\- O( .i-ion 

 io r.i. r to thi> in another connection. 



I hiring tin- pio^ress of the experiment-- ^mie hlt\ ->|M-cimen-. 



\\ i te . i\ ailal ile. .UK I tin- general healt h and \ i^or m.i\ In- intei "i < I 



lioin tin- I. iet th.n in the three and one half month- not .1 >in-|- 



-pi -i imeii died oi e\en showed signs of detei i. n ,n ion. except .1- a 



in I. id i i re of the brilliance of coloration ma\ ha\e been indica- 



ti\ e ol -mil. t are was taken to suppK 1 1 from time to time, 



.iluio-t d.iil\. -uch as came in from plankton haul- \\hich \\eic 

 -up|ilied to tin- lo,.!))- quite regnlai'K . and this m.i\ ha\e con- 

 tributed to tin- . \. ellent conditions of health already alluded to. 



.^[>iri>^nif>hi.\ -eem> to take ratln-r natnralK to the aquarium 



environment and soon becomes quite at home so far as one may 



judge I mm appeal .nice. >peiinien- reqmri- Irom I \\ o lo several 



da\- lirmK \<> att.uh ihem-el\es to the bottom or sides of the 







aquarium. Thi- i- accompli -lied b\ an adhe-i\ e se< r< lion ol the 

 \\orm \\hich i- di-char^ed through a -mall pore at the l<i\\er end 

 of tin- tube. Tin- time required for attachment max be \aried 

 \>\ having the bottom of the aquarium covered \\ith .1 la\er ol 

 >and or b\ |ilacinu fragments of rock in contact \\ith the ba-e o| 

 the tube-. While in most cases tin- -pecimen- attach tln-m-el\e- 

 \\ln-n-\er tlu\ hapj>en to be placed, which i- fortunate in -uch 

 experiment- a- tln^e under consideration, -till it not infn-queiuly 

 happen- that a specimen will go through various irau-lator\ 

 movements before finally settling do\\n. It ma\ be noted that 



