144 



Papers from the Department of Marine Biology. 



Table 4. — Record for 1 to 6 days — Continued. 



[Forty specimens, one half of each one pulsating under the control of its sense-organs, while a 

 circuit wave of contraction was maintained in the subumbrella muscles of the other half 

 (fig. 10). The letter C after the measurement for any day indicates that the central cavity 

 had been filled by the regenerated tissue.] 



Specimen. 



|Half with S. O . . . . 

 [Activated half. . . . 



JHalf with S. O 



[Activated half. . . . 



f Half with S. O 



\Activated half . . . . 



[Half with S. O 



[Activated half. . . . 



JHalf with S. O 



[Activated half. . . . 



fHalf with S. O 



[Activated half. . . . 



No 29 ^^^'^ "^'^^^ S. O . . . . 



\Activated half. . . . 



JHalf with S. O . . . . 



[Activated half. . . . 



[Half with S. O . . . 



[Activated half. . . . 



[Half with S. O . . . 



[Activated half. . . , 



[Half with S. O . . . 



[Activated half. . . 



|Half with S. O . . . 



[Activated half. . . 



[Half with S. O . . . 



[Activated half. . . 



JHalf with S. O . . . 



[Activated half. . . 

 j^^ 3^ JHalf with S. O . . . 



[Activated half. . . 



jHalf with S. O . . . 



[Activated half. . . 

 ,, „„ /Half with S. O . . . 

 .\o. ciy \ Activated half.. . 



|Half with S. O . . . 



[Activated half. . . 



Mean for all observations: 



Half with S. O . . . 



Activated half. . . 



No. 23 



No. 24 



No. 25 



No. 26 



No. 27 



No. 28 



No. 30 



No. 31 



No. 32 



No. 33 



No. 34 



No. 35 



No. 36 



No. 38 



No. 40 



1 daj'. 



2.75 

 2.25 

 2.50 

 2.00 

 1.25 

 1.00 

 3.00 

 2.25 

 4.00 

 3.25 

 2.75 

 2.00 

 1.75 

 1.00 

 2.50 

 2.00 

 1.50 

 1.00 

 3.00 

 2.25 

 2.25 



75 

 00 

 .75 

 75 

 00 

 ,00 

 .25 

 .50 

 .25 

 .75 

 .00 

 .00 

 1.50 

 4.00 

 2.75 



2.65 

 2.00 



2 days. 



4.25 

 3.50 

 4.00 

 3.25 

 3.50 

 3.00 

 5.00 

 3.50 



3.25 

 4.00 

 3.00 

 3.50 

 3.00 

 4.25 

 3.50 

 3.75 

 3.00 

 3.50 

 2.75 

 4.00 

 3.25 

 4.00 

 3.25 

 5.00 

 3.50 



3 days. 4 days. 



6.00 

 5.00 

 5.75 

 4.75 

 5.50 

 4.75 

 6.50 

 6.00 

 9.00 

 8.25 

 5.75 



00 

 25 

 75 

 25 

 00 

 ,50 



4.05 

 3.27 



4. 



5. 



4. 



5. 



4. 



5. 



4. 



5. 



4. 



5 



4, 



5 



4 



5 



4 



5 



4.75 



7.25 



5.00 



5.75 



4.50 



5.50 



4.75 



8.75 



7.50 



5 . 75 



4.67 



75 

 50 

 25 

 75 

 75 

 50 

 75 

 75 

 75 

 50 

 25 

 50 

 75 

 50 

 75 

 75 



7.50 

 6.25 

 7.75 

 6.25 

 7.25 

 6.00 

 9.00 

 7.50 



8.00 

 6.50 

 7.25 

 6.00 



.75 

 .50 

 .50 

 .25 

 .50 

 6.25 

 7.50 

 5.75 

 7.75 

 6.25 

 7.75 

 6.25 

 8.00 

 6.50 

 9.25 

 7.50 

 7.75 

 6.25 

 7.75 

 6.25 



7.63 

 6.15 



5 days. 



9.00 

 7.50 

 9.25 

 7.50 

 9.00 

 7.00 



9.50 

 8.00 

 8.50 

 7.00 

 9.00 

 7.25 

 8.75 

 7.25 

 8.50 



50 



00 



25 



00 



00 



9.25 



7.50 



9.25 



7.00 



9.25 

 7.00 

 8.75 

 7.25 



9.00 

 7.23 



As was pointed out previously, the stimulus for pulsation originates, 

 at any given time, from a single sense-organ, and pulsation will be 

 continued at nearly its normal rate by a medusa upon which a single 

 sense-organ remains. To test the efficacy of a single sense-organ to 

 control activities other than muscular contraction a series of disks 

 prepared as above described (except that each ''active" half-disk had 

 a single sense-organ) were used in a parallel series of regeneration 

 experiments. In all instances such active disks showed an unusual 

 irregularity in the rate of pulsation, since there was present no other 

 nerve-center to take up the initiation of impulses causing pulsation 

 whenever the rate of discharge of the single organ fell below normal. 



