158 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 



tlie larger segments as regards the deprivation of 

 oxygen. This is shown by the greater regularity 



of Anrelia. The following experiment exemplifies this particular 

 rule even more prettily than does the one quoted in the text, 

 from the fact that the segments survived the operation for a 

 greater number of days. 



An Aurclia having a regular and well-sustained rhythm of 

 twenty per minute was divided as already described in the text. 

 In five-minute intervals on successive days the average rates of 

 the four segments were as follows : — 



