E. W. BEEGER ON THE CUBOMEDUS^E. 37 



minutes more only three. There was a long latent period two or 

 three seconds before the stimulation of cutting off the arm made 

 itself evident in the rhythm. 



A second oral lobe was removed. Then there followed twenty-four 

 pulsations, a pause of two seconds, and two pulsations, in all twenty- 

 six pulsations to a minute. The rate of pulsation soon fell to the 

 previously abnormal low rate. 



Third lobe removed: 21 pulsations in first half minute and then 

 16, or 37 per minute. 



Fourth lobe removed: 17 pulsations in first half -minute plus 13 

 gives 30 for the minute. 



No difference in the coordination of the animal was shown as a 

 result of the removal of one-half the number of oral arms. 



Fifth lobe removed : 17 pulsations plus 15 equals 32 to the minute. 



Sixth lobe removed : 17 in first half -minute plus 4 in the second 

 half-minute gives 21 pulsations for the minute. 



Seventh lobe removed : 17 plus 9, or 26 per minute. 



In all these instances the rhythm in the second half of the first 

 minute was irregular and intermittent. 



Seventeen and then seven pulsations were provoked after the 

 animal had become quiescent, or nearly so, by merely handling it. 



45. Eighth oral lobe was removed and pulsations stopped. The next 

 day the animal was in good condition. The pulsations counted in the 

 evening were 12, 14, 14, 11, per minute. The rhythm was not 

 regular ; there was a tendency to groups of twos, threes, or more, but 

 no prolonged intervals of rest were observed. When placed into 

 fresh sea- water, the pulsations were fourteen to the half -minute or 

 twenty-six to the minute ; seventeen to the half-minute, and thirty- 

 three to the minute were also counted. This specimen gave spon- 

 taneous contractions during two weeks, after which it was thrown 

 out, the aboral end being eaten through and little or no regeneration 

 having taken place. 



46. Two more were operated upon : A. Its rhythm was 18, 14, 17. 

 Its entire margin was cut off. The separate pieces of the margin 

 pulsated, 6, 7, 4, 6, 7, 9. The animal seemed paralyzed by the 

 operation; it responded by a contraction now and then to stimu- 

 lation but gave no spontaneous pulsations. B. Its rhythm was 17, 

 15, 12, 12. All its oral arms were removed. Its rhythm was only 

 raised to seventeen and not perfect. In twenty-five minutes it had 

 fallen to eleven, in four hours to ten pulsations [per minute]. 



