156 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 
in this connection it is interesting to observe that, 
although the endurance of the smaller segments 
attached to a bucy in the sea. Four days afterwards some of the 
specimens were putrid, while others were as fresh as they were 
when first operated on. Again, as an instance of the experiments 
in segmentation of Sarsia, I may quote an experiment in which a 
score of specimens were divided in all sorts of ways, such as 
leaving the manubrium attached to one half, or three marginal 
bodies in one portion and the remaining marginal body in the 
other portion, etc. Yet, although it was very exceptional to find 
the two portions presenting an equal degree of endurance, no 
uniform results pointing to the cause of the variations could be 
obtained. In most cases, however, the energy, as distinguished 
from the endurance of the larger segments, was conspicuousiy 
greater than that of the smaller. (But it is curious that in many 
cases the effects of shock appeared to be more marked in the 
larger than in the smaller segments—the latter, for some time 
after the operation, contracting much more frequently than the 
former.) To show both these effects, one 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 #. 
pipetted go Minutes of rest. pire Bes pul- Minutes of rest. 
20 0 0 5 
4 4 10 2 
15 5 46 1 
6 3 23 2 
49 i 
900 1 
45 12 117 1 
1145 13 
| 
To show the difference between the endurance of two halves of 
a bisected specimen of Sarsia, I may quote one experiment which 
