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



of response, and I see no essential difference between 

 the rhythmic motions of the simplest organism and 

 those of a deganglionated Medusa in acidulated 

 water. Lastly, the facts relating to the tonus of the 

 manubrium in Sarsia furnish very striking, and I 

 think almost conclusive, proof of the theory which 

 I have advanced. 



