68 Animal Life by the Sea-shore. 



food-fragments. Althougli usually attached by means of a 

 sticky secretion from the base of the body to rocks, shells, etc., 

 sea-anemones have the power of shifting their position by slow, 

 gliding movements of the basal extremity ; more rarely loco- 

 motion is effected by means of the tentacles, which are then 

 used as little feet. They feed almost entirely on living animals ; 

 any small fish or crustacean coming within reach is seized by the 

 tentacles, the urticating organs of which have a paralysing 

 effect, soon putting an end to its struggles, after which it is 

 swallowed entire. 



The Sea-anemones have the sexes separate ; in a few forms 

 the eggs are discharged through the mouth, and undergo their 

 development in the sea ; in the majority, however, some part 

 of the development takes place within the bodj' of the parent ; 

 in the Wartlet, for instance, the young reach their full develop- 

 ment in this position. A few 

 forms, e.g., the Plumose Anemone, 

 are known to be capable of repro- 

 ducing themselves by an asexual 

 process, small buds being formed 

 from the base of the animal. 



As we have seen, the anemones 

 have the body quite naked, and 

 trust to their stinging organs for 

 protection from predaceous animals ; 

 allied polyps are, however, known, 

 FIG. 82. — CUP-CORAL. wMcli sccretc hard, calcareous skele- 

 tons. These are theMadrepore Corals, 

 also known as Stone-corals. A few are solitary, like the sea- 

 anemones, but in the majority continuous budding has led to 

 the formation of enormous aggregations of individuals, which 

 participate in a common life, and form what are known as 

 colonies. Madrepore colonies are particularly abundant in the 

 warmer oceans, where they build coral reefs of great size. The 

 only British representative is a solitarj' form, the little Cup-coral, 

 Caryophyllia sniithi (Fig. 82), which occurs in the Channel, and is 

 sometimes not imcommon at low water, under boulders or in the 

 crevices of rocks. The living animal has the appearance of 

 a little anemone, for the skeleton is completely concealed, 

 and when dried presents the form of a little cup, the inside 

 of which is divided up by a number of radially arranged, 

 stony partitions. 



The Madrepores are not the only colonial polyps to which 

 the name " coral " is given ; thus the precious coral of 



