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 buoy 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 

 scoi'e of specimens were divided in all sorts of ways, such as 

 leaving the manubrium attached to one half, or three marginal 

 bodies in one poi'tion 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 conspicuously 

 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, conti-acting 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 : — 



To show the difference between the cnduranre of two halves of 

 a bisected specimen of Sarsia, I may quote one experiment which 



