SEA ANEMONES AND CORALS 



41 



form and color. The)' vary in size from that of a pin's liead to 

 several feet across, and they live at all ilepths and in a great variety 

 of situations. 



A. coral polyp is only a sea anemone which deposits a plate of 

 lime salts at the base of its barreldlke body and between the 



Fig. !6; Star-Coral Showing Living Poly|3s. From a Specimen in tlie New Yoric A<iuarinm. 



radial partitions of the stomach cavity. These lime salts form 

 a stony "skeleton" or sulistiince which we commonly call "coral." 



It is well to remeniber that the coi-al animals are not "insects" 

 but are merel_y sea anemones which foiun stonv 'skeletons." 



AltliOLigh sea anemones and coral polyps resemble beautiful 

 flowers when fully expanded, they quickly contract into a mere 

 dome-shaped mass when disturbed. In this way the coral polyps 

 are protected by withdrawing into their stony cnp-shaped bases. 



