BY THE SEASIDE— ANIMAL LIFE 



colony. On the outside of each cavity containing 

 a member of the colony there is a structure which 

 resembles nothing so much as a hawk-like bird's 

 head atop of a long neck. While the tentacles wave 

 in the water, the bird's head snaps vigorously, 

 moved here and moved there. The birds' heads, 

 which might be mistaken for parasites stealing food 

 from the waving tentacles, really perform the useful 

 function of keeping them clean and warding off 

 creatures which might do them harm. 



Now let us pass to quite different though equally 

 common sea shore animals, the star fish. There 

 are very many kinds but the common starfish will 

 serve our purpose well. We may make a beginning 

 by examining his back under a low magnification 

 and observing that it is protected by a number of 

 hard plates which form a very efficient armour. 

 At the point where two of the rays (the finger like 

 structures) arise we shall notice a small fiat plate, 

 j this too is worth a moment's inspection, for it is 

 j the water pore through which the starfish takes in 

 water. 



The under surface of the starfish shows us of 

 course its mouth in the centre of its body, the soft 

 fleshy suckers which cover the rays, with the excep- 

 tion of a narrow line down the centre of each one. 

 At the tip of each ray there is an eye; it may 

 easily be distinguished by its bright red colour and 

 microscopic examination will show us that it is quite 

 unlike any of the other eyes we have examined. 

 Over each eye there is a little tentacle; these little 



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