254 



ZOOLOGY 



other, the "basket-fish," the arms are branched.' The ser- 

 pent-stars - five in crevices of the rock and, being of rather 

 small size, are not commonly seem. At the base of the arms, on 

 the right and left, are a pair of slits, which form the exits from 

 pouches into which the reproductive glands open (Fig. 246j. 

 In certain species the pouches are used for brooding the 

 young. 



The basket-fish occur in Northeastern waters, from low tide 

 to one hundred fathoms, and are often brought up by fisher- 



FlG 



■ Am phi ura squarnrdn. Orir' of tho Ophiurid^e. Nat. size. 

 Photo, by W. II. C. P. 



men, to whose lines they are led 1iy their instincts to cling. 

 The liranching of the arms enal iles the animal to hold its prey, 

 which consists of shrimp and fish. 



The sea-urchins, or echinoids, may be regarded as starfi.shes 

 in which the arms have shortened and the disk enlarged so 

 as to fill up the interspaces, and make a solid, nearly spherical 

 form. The sea-urchins eat various small animals and get food 



' Fig. 246. 



- Of the serpent-stars there are two eoiiimon forms on the New EngUind 

 coast, — a white speeies, with long, slender arms, Amphiura squamata (Fig. 

 24.5), and the spotted Ophiopholis, which lias shorter, stouter arms. 



