MODE OP PROGRESSION. 



127 



impediment, be in the path of its progress, the 

 star-fish does not seem to trouble itself in the 

 least, but continues its still, gliding movement, 

 as quietly as if it were moving on level ground. 

 As the stone is reached, one ray of the star-fish 

 is gently pushed upwards, and seems to adhere 

 to the stone ; another follows, then a third, and 

 presently the creature is seen to climb the stone 

 with quite as much ease as if it were walking on 

 level sand. The rays accommodate themselves, 

 in a very curious manner, to the shape of the 

 substance over which the animal is crawling; so 

 that if it is passing over a sandy spot, interspersed 

 with furrows and pebbles, the arms of the star- 

 fish never bridge over the furrows, but pass down 

 one side and up the other, while precisely an 

 opposite process takes place with regard to the 

 pebbles. The star-fish can thus climb rocks that 

 are perpendicular, and clings firmly even when 

 they overhang. How this process is conducted 

 we shall presently see. 



I may as well remark here, that if the star- 

 fish were dead when put into the water, the 

 observer would find his patience well tried if he 

 waited to watch for these movements, so that he 

 ought to be quite sure whether he has hit upon 

 a specimen that is living. Now, however dead a 



