THE ECHINODERMATA 



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abundant on sandy shores. During the severe 

 winter of 1894-5, when the Mersey at Liver- 

 pool was frozen nearly for one memorable day, 

 and filled with floating ice for many more, I 

 saw the shore beyond New Brighton heaped all 

 along with a bank, often two feet across, of the 

 common Heart-Urchin. These, which afforded 

 a fine feast for the hungry sea-gulls, had been 

 killed by the intense cold, and afterwards washed 

 ashore by the tide. The vast numbers of this 

 creature which exist on that coast were thus 

 unexpectedly brought to light. 



These animals are sometimes described as 

 " burrowing " creatures, because they live covered 

 in sand. The term is rather misleading. Far 

 from wishing to burrow, they spend their lives 

 in a constant struggle with sand that closes over 

 them only too readily ; and their whole structure 

 is adapted to prevent their sinking in a quicksand. 



We began our chapter with the Sea-Urchins, 

 because they are the most important members of 

 the group to which they give their name ; but 

 there are forms belonging to the Echinodermata 

 that are more familiar to the ordinary observer 

 the Starfishes. Those who take an interest in the 

 cultivation of the oyster find them far too familiar 

 for the starfish is the oyster's deadliest foe, not 

 even excepting man. 



The common Starfish, Asterias rufons, may 

 constantly be found among stones, about low- 

 tide mark. Its manner of walking is peculiar and 

 characteristic. On the under surface of each ray 

 are rows of white sucker-like tube-feet, which can 

 either be drawn in or pushed out. By doing each 

 alternately the animal walks. First the feet are 

 extended to their full length ; then the terminal 

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