34 



L.essojis III Zoology 



and muscles attached to them they form a powerful ap- 

 paratus called the lantern. Inside the shi-l's from which 

 the lantern has been removed, can be seen five projections 

 to which some of these muscles were attached. With its 

 teeth, nhich are constantly growing at the root as they 

 are worn away at the tip, the sea-urchin scrapes seaweeds 

 o£E the rocks, as it walks about mouth downward, and it 

 also feeds upon dead fish. 



Fig. 1. 



The searurchin walks with tube-feet, as the star-fish 

 does, but its suckers are smaller and more nearly the 

 color of the spines. If we have only dried specimens, in 

 order to see the tube-feet we must look steadily and pa- 

 tiently on the under s-ide of the shell. Children will see, 

 after a little thought, that they are largest on this side 

 because they are used most in walking. But how can the 



