42 



ZOOLOGY. 



Fig. 41.— Antedon, stalked and free. 



attached to rocks; stalked when young, it eventually be- 

 comes free. 



Class II. — Asteroidea. 



General Characters of Star-fishes. — The star-fishes in- 

 clude the snake- or sand-star (Fig. 42), and the common 

 five-finger, Asterias vulgaris (Fig. 43). This and the allied 

 varieties are abundant on mussel and oyster beds, being 



very injurious to the latter, 

 which serve them as food. 

 The star-fish projects its 

 capacious stomach between 

 the open valves of the oy- 

 ster, and sucks in the soft 

 M parts, in this way doing 

 much damage to the oyster- 

 beds of the southern coast 

 of New England. 



All star-fishes grow from 

 eggs. After swimming 



Fig. 42. -Sand-star. Natural size. about &g a j; ttle c ili ;lt Ccl 



sack (gastrula), arms grow out, and it appears much as in 

 Fig. 45. 



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