CHAPTER XVIII. 

 ECHINODERMATA. 



STUDY OF A LIVE STARFISH. 



STUDENTS who can visit the coast may make profitable study 

 of starfishes in their native haunts. At low tide wade along the 

 shore, looking in tide pools, among rocks and seaweeds, under 

 wharves, etc., for starfishes. Are they found in any special 

 situation ? Are they more abundant on one kind of surface 

 than another ? Do they seem to prefer sheltered places ? Has 

 their color any relation to their surroundings ? Are they found 

 in strong light, or. do they seem to prefer shaded spots ? Do 

 they move ? If so, at what rate ? Do you find them on the 

 vertical walls of rock ? Can they climb ? Do they adhere to 

 the surface ? If so, how strongly ? Try to pull one away from 

 a smooth surface on which you find it. Are they extended flat, 

 or more or less curled up ? Are the rays evenly spread out ? 

 Do they change the position of the rays to any extent ? Are 

 they found singly or in groups ? Do they seem to live in col- 

 onies ? Do you find them eating ? If so, what do they eat, 

 and how ? Has the situation where you find them in numbers 

 any relation to a food supply ? Have they any preference as to 

 the temperature of the water ? Are they seriously affected by 

 extreme changes in temperature ? At how great depth are they 

 found ? Have starfishes any natural enemies ? Have they any 

 means of defense ? As you reach out to take a starfish, does it 

 seem to be aware of your presence ? Is it affected by strong 

 light ? By your shadow ? By additional heat ? By sound ? 

 Does it in any way appear to shrink away from you as you take 

 hold of it ? Has it any means of stinging or irritating your hand? 



Put a live starfish in an aquarium filled with sea water and 

 watch it. Does it move about? Does it crawl up the sides? 



177 



