On the Nervous System of Cassiopea Xamachana. 



143 



contracting normally under the influence of its sense-organs, while all 

 the sense-organs are removed from the other half and a circuit wave of 

 contraction maintained in a labyrmth of its subumbrella muscles. In 

 a disk prepared in this manner the rate of pulsation of the activated 

 half will vary from 3 to 10 times that of the normally contracting half. 

 The comparative rates of regeneration for 40 disks under these 

 conditions are shown in table 4 and figure 9. 



Table 4. — Record for 1 to 5 days. 



IForty 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.] 



