338 NATT7KAX HISTOKT. 



the animal which is represented in Fig. 9. On its under 

 side are great numbers of little feet. "With these it walks 

 along on the bottom of the sea, searching for food, which 

 it puts into its mouth, this being in the centre of the star 

 on the under side. These feet are fleshy, and are hollow 

 tubes, like the tentacles of the Actiniae (§ 577). They are 

 so shaped that they can be used as suckers, and the animal 

 can shorten and lengthen them at pleasure. It is by 

 pumping water into and out of them that the suction is 

 effected . In walking, the suckers are some of them thrown 

 forward, and, taking hold of the surface on which the an- 

 imal is, and then shortening, they draw it forward. It 

 can walk up the side of a smooth rock in this way. The 

 operation can be seen by placing one of these animals in 

 a glass vessel filled with water. If you j)lace a Starfish 

 in your hand on its back, that is, with its feet upward, 

 you will see these little suckers reaching forth in all di- 

 rections ; and if you look at them with a magnifying 

 glass, you will observe a ring-like arrangement in each 

 sucker as it lengthens out, quite as plainly as you see it 

 in a common worm. 



585. These animals not only walk with these suckers, 

 but they seize their prey with them. They are carniv- 

 orous and rapacious ; and in taking their prey they fasten 

 their suckers to it, and work it up to the central mouth, 

 which is opened wide to receive it. 



586. Besides the motion of the suckers, the five arms 

 on which these are can be moved also in various direc- 

 tions. In some species there are little red spots at the 

 ends of the rays, which are supposed by some to be 

 eyeg ; but this is very doubtful. 



1581. The order Stellerida, to which the Starfieh be- 

 longs, includes a large variety of animals having a gen- 

 eral resemblance, but varying in the relative proportion 

 of the body and the rays, and the arrangements of the 

 latter. In some species there is little else but arms, while 

 in others the central part is large. 



