STARFISHES 161 



a number usually live in company; but there is no difficulty 

 in obtaining this and many other species of interesting starfishes 

 in fishing towns and villages where trawlers are stationed, for 

 they are being continually found among the contents of the net. 



Although the Feather Star can hardly be described as an active 

 creature, yet it will cover a considerable amount of ground in the 

 course of a day, creeping over rocks and weeds by means of its 

 arms, which are raised, extended, and again depressed in succession, 

 each one thus in turn serving the purpose of a foot. These arms 

 are capable of being moved freely in any direction, as are also the 

 little more or less rigid pinnules appended to them. The latter 

 are bent backwards on an extended arm that is being used to pull 

 the animal along, so that they form so many grappling hooks that 

 hold on the bottom ; and then the arm in question is bent into a 

 curve by the contraction of its muscles, thus dragging the body 

 forward. The arms on the opposite side of the body are also used 

 to assist the movement by pushing it in the same direction, and 

 this is accomplished by first bending the arms, and then, after 

 curving the pinnules in a direction from the body, again extending 

 them. Other movements of the feather star are equally interest- 

 ing. Thus, the manner in which it will suddenly extend its arms 

 and apply its pinnules to the surface on which it rests in order 

 to obtain a good hold when alarmed, and the way in which it 

 apparently resents interference when one of the arms is touched, 

 are worthy of observation. The arms themselves are readily 

 broken, and will- continue to move for some time after being 

 severed from the body, but the loss to the animal is only tem- 

 porary, for a new arm grows in the place of each one that has 

 been broken off. 



This tendency to break into pieces is much greater in the 

 Brittle Stars, as might be expected from their popular name ; and 

 is, in fact, such a marked characteristic of the group that it is not 

 by any means an easy matter to obtain a collection of perfect 

 specimens. They will often snap off all their arms, as if by their 

 own power of will, when disturbed or alarmed, and even when 

 removed from their hold without injury, they will frequently 

 break themselves into pieces if dropped into spirit or in any way 

 subjected to a sudden change of conditions. 



The tube-feet of Brittle Stars are very small and are not pro- 

 vided with suckers, but are very sensitive, serving the purpose of 

 feelers ; also, having thin, permeable walls, they probably play a 



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