68 ANIMALS OF THE SEASHORE 



Corals resemble sea anemones except that the 

 former are colonial and secrete a limey skeleton. Al- 

 though the individual coral animals are usually 

 small, the colony may reach a great size, forming 

 immense reefs in the sea. After the individuals of 

 one generation die, those of the next generation grow 

 on top of the dead skeletons increasing the size of the 

 reef. Sometimes these reefs extend above the sea 

 and we find whole islands made up of the dead skele- 

 tons of these coral animals. 



The coral polyp (often erroneously termed "in- 

 sect") may be of various colors and is really like a 

 minute sea anemone. A living mass of coral is really 

 quite different from the dried skeleton with which 

 we are more familiar. It feels soft and fleshy be- 

 cause of the many tentacles of the individual polyps. 



With a few exceptions, corals live exclusively in 

 tropical seas where the water is warm throughout 

 the year; the most common exception, Astrangia 

 danae, lives as far north as Cape Cod. 



Sea Fans, Sea Pens, Sea Trees and the like are 

 modified corals, many of which have a horny skele- 

 ton instead of a calcareous one. Although many 

 species are tropical, a few live in temperate waters. 

 The Sea Tree, Leptogorgia virgulata, is a conspicuous 

 member of the fauna at certain places off the New 

 Jersey coast. 



Sagartia luciae Verrill (Striped Sea Anemone) 



PLATE III. Fig. 11 



A very individual form — olive green body with 

 orange stripes. Grows on shells, rocks or seaweed 



