148 JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 



These observations may be taken as samples of 

 others which it would be unnecessary to quote, as 

 it will be seen from the above that there is no pre- 

 cise relation between the number of the pulsations 

 and the duration of the pauses. Nevertheless, thai 

 there is a general relation may be seen from some 

 cases in which unusually prolonged pauses occur. 

 Tlie followino: instance will serve to show this: — 



Sarsia (another specimen). 



Tn this case, the relation between the long pause of 

 380 seconds and tlie subsequent prolonged swim- 

 ming bout of 112 pulsations is obvious; also, as 

 the latter was then followed by a short pause of 

 twenty seconds and another comparatively short 

 bout of forty-five pulsations, the refreshing influence 

 of the previous 380 seconds rest may be supposed 

 to have been not quite neutralized by the exhausting 

 effect of the foregoing 112 pulsations. At any rate, 

 looking to the general nature of the previous pro- 

 portions (viz. in their sum ^jj), it is certain that 

 ff I leaves a large preponderance in favour of nutri- 



