E. W. BERGER ON THE CUBOMEDUS^E. 35 



in a jar of about twenty centimeters in diameter. It came to the 

 surface every now and then, after eight to fifteen pulsations. The 

 tentacles and the phacelli were of a lilac shade. If a pencil was 

 placed in its way it would pulsate against it repeatedly without any 

 effort to dodge around it. 



6.58 A. M., 124 pulsations were counted to the minute. 



8.00 " 124 " " 



9.25 " 136 



10.15 " 131 

 11.00 " 



At 10.15 it went around the dish in eight seconds, taking eighteen 

 or nineteen pulsations. If a bright platinum spatula or a black 

 pencil was placed in its circuit it would repeatedly butt against 

 it each time it came around. After the second or third pulsation 

 against it, however, it seemed to have some sense to change its 

 direction. 



b. The pedalia have no perceptible action of their own. They 

 move inwards slightly toward the axis at each pulsation, but 

 scarcely as much as one would suppose from their attachment to 

 the pulsating margin. It seems as if they were for "winging" the 

 moving animal more than for anything else. 



c. The velarium is loose and it flaps. It seems to take part in 

 swimming something more than the passive diaphragm function, 

 i. e., it straightens out during the recovery after each contraction of 

 the bell. 



AURELIA AND POLYCLONIA. 



[The following experiments were performed at Port Henderson, 

 Jamaica, in 1896.] 



42. May 12th. An Aurelia was pulsating normally at the rate 

 of twenty-five or twenty-six pulsations to the half-minute. One 

 lithocyst was cut out, when a few contractions, evidently caused by 

 the stimulus of cutting, followed; then, rest. In the first minute 

 there were only about five pulsations. In two or three minutes 

 rhythmic pulsations were resumed. Four minutes after the cutting 

 there were nineteen pulsations to the half-minute. About twenty 

 minutes after there were nine to the half-minute, in groups of six 

 and three. 



