Movements of Star-fish 63 



ments of this kind are hindered or altogether 

 abolished. If both the visual and tactile sen- 

 sory organs of one of these animals are removed 

 the creature ceases to move, but if fed it may 

 continue to live. 



Although it is difficult for star-fish to move 

 from one place to another unless by means of 

 their sucker feet, it is possible for them to 

 shuffle along when placed on their backs. They 

 accomplish this movement by aid of their 

 pincer-like spines, which under these conditions 

 act together in a remarkable manner so as to 

 push the animal along in a continuous direc- 

 tion. If while progressing in this manner a 

 lighted match is held near the animal, as soon 

 as the heat reaches it the whole of its spines 

 reverse their movement, and work in the oppo- 

 site direction. 



Movements similar to those above referred 

 to take place in the recently amputated arm of 

 a star-fish. They are distinctively purposive in 

 character, and depend on energy set free by 

 external stimuli acting through sensory organs 

 on the sub-ectodermal plexus of nervous 

 matter, to which we have referred. In a short 



