ME, Gr. J. ROMANES ON THE LOCOMOTOR SYSTEM OF MEDUSAE. 
671 
fested by the smaller than by the larger segments in the stale water ; and the fact is 
presumably to be accounted for by the consideration that the ganglia in the smaller 
segments were more potent than those in the larger. 
experiment may be quoted. A specimen of Sarsia was divided into two parts, of which one was a quadrant. 
Immediately after the operation the results were as follows : — 
Portion £. 
Portion J. 
Number of pulsations. 
Minutes of rest. 
Number of pulsations. 
Minutes of rest. 
20 
0 
0 
5 1 
4 
4 
10 
2 
15 
5 
46 
1 
6 
3 
23 
2 
49 
1- 
45 
12 
900 
1 
117 
1 
1145 
J 
To show the difference between the endurance of two halves of a bisected specimen of Sarsia, I may quote 
one experiment which was performed on the same specimen as the one mentioned in the text to show the 
general relationship between the duration of the pauses and that of swimming-bouts (see last footnote). 
Immediately after Bisection. 
iA. 
Number of 
Seconds of 
Number of 
Seconds of 
pulsations. 
rest. 
pulsations. 
rest. 
56 
10 
82 
180 
150 
150 
51 
20 
68 
335 
14 
60 
130 
30 
13 
50 
46 
45 
46 
45 
2 
10 
38 
65 
99 
66 
18 
45 
103 
360 
23 
60 
12 
4 
35 
130 
105 
70 
Pauses now become longer, and 
swimming-bouts shorter. 
I 
Twenty-four hours after the Operation. 
i A. 
*B. 
Number of 
Seconds of 
Number of 
Seconds of 
pulsations. 
rest. 
pulsations. 
rest. 
2 
363 
50 
20 
12 
362 
81 
25 
4 
666 
37 
101 
25 
' 300 
2400 
60 
