198 ZOOLOGY 



guinolenta 1 (Fig. 181). Certain starfishes have many 

 arms instead of only five, as in the case of Solaster 2 endeca 3 

 of the northern Atlantic (Fig. 182). In still other star- 

 fishes the rays are partially connected by a membrane like 

 the web of a duck's foot, so that the whole outline is 

 nearly pentagonal (Fig. 183). 



The Ophiuroidea. In the Ophiuroidea 4 the organs are 

 not prolonged from the disk into the arms, consequently 



FIG. 184. Amphiura squamata. One of the Ophiuridae. Nat. size. 

 Photo, by W. H. C. P. 



the arms may be thrown off without injury to the animal ; 

 hence the name "brittle-star." The brittle-stars fall 

 into two groups, in one of which, the serpent-stars, the 

 arms are unbranched, while in the other, the "basket- 

 fish," the arms are branched. 



Of the serpent-stars there are two common forms on the 

 New England coast, a white species, with long, slender 

 arms, Amphiura 5 squamata 6 (Fig. 184), and the spotted 

 Ophiopholis, 7 which has shorter, stouter arms. The 



1 Blood-red. 5 dfj.<f>l, round about ; ofy><, tail. 



2 sol, sun ; aster, star. 6 Scaled (squama, a scale). 

 8 ^Se/ca, eleven. 7 00is, snake ; 0o\/s, scale. 



4 00ts, serpent ; ovpd, tail. 



