42 



SEA-SHORE LIFE 



Sea anemones are found in all oceans, but the stony corals are 

 practically confined to tropical and sub-tropical regions and will 



not usually live in water which 

 is colder than C)fi° F. In the trop- 

 ical Atlantic and Pacific thousands 

 of coral islands called atolls have 

 been gradually built up by the con- 



stant growth of coral polyps, and 

 every grain of sand on the Baha- 

 mas, Bermudas, or Florida Keys 

 was once part of the skeleton of a 

 coral polyp or belonged to some 

 animal or plant which lived among 

 the coral reefs. 



The Star-Coral, (Astrangia 

 dance, Figs. 16, 17 J. This stony 

 coral extends farther into the tem- 

 perate zone than any other species, being found from the Carolinas 

 to Cape Cod. It is abundant in Long Island Sound where it 

 forms encrusting masses of 

 star-like cups upon stones, dead 

 shells, etc. 



The coral polyps are glassy 

 white, and translucent, and 

 have each from eighteen to 

 twenty-four long, tapering ten- 

 tacles Avhich end in a Avliite 

 knob and are speckled over 

 with white warts. These are 

 the stinging organs which en- 

 able the coral to capture its 

 prey of small marine animals. 

 When fully expanded the pol- 

 yps are about one-eighth of an 

 inch wide and three-eighths 

 high, but when disturbed they 

 suddenly contract so as to become practically invisible. The colony 

 starts with a single polyp but soon others bud out from its base, 



Ftg. iS ; FLESHY CORAL. 

 Woods Holl, Mass. 



