III. 



STAR-FISHES, SEA-URCHINS, AND SEA-CUCUMBERS. 



It is not often that one has the pleasure of meet- 

 ing with star-fishes on the New Jersey coast, but 

 yet they are occasionally seen, perhaps more fre- 

 quently in the north, and thus they deserve a place 

 here. The commoner form [Asierias berylinus, PI. 

 5, Fig. 3) is a fairly large species, of a more or less 

 greenish color, sometimes inclining to brown, and 

 roughly covered with tubercles. Its five arms, at 

 the extremity of each of which is situated a single 

 red eye-speck, are somewhat irregularly disposed, 

 and not rarely one is stumpy through breakage or 

 unequal development. 



It is interesting to watch the movements of the 

 star-fish. From the under surfaces of the arms, at 

 whose union is situated the central mouth, a great 

 number of delicate tubules, each one terminated by 

 a minute sucking-disk, may be seen to be vigor- 

 ously in motion, the whole series undulating like 

 wind-swept grain. These tubules are hollow and 

 fed from within with sea-water, the increase or 

 diminution of which within the tubules, regulated 

 at the will of the animal, determines the length to 

 which they may be extended or protruded. At- 

 taching themselves to foreign objects by means of 

 their sucking-disks, the animal may in this way be 

 D 7 73 



