338 NATURAL HISTORY. 
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 
onthe under side. These feet are fleshy, and are hollow 
tubes, like the tentacles of the Actiniz (§ 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 place 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 2 common worm. 
585. These animals not only walk with these suckers, 
but they seize their prey with them. They are carniy- 
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 
eyes; but this is very doubtful. 
587. The order Stellerida, to which the Starfish 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. 
