SECRETS OF THE OCEAN 149 



Some of the starfish are covered with long spines, 

 others are nearly smooth. The colours are won- 

 derfully varied, red, purple, orange, yellow, etc. 



The stages through which these prickly skinned 

 animals pass, before they reach the adult state, 

 are wonderfully curious, and only when they are 

 seen under the microscope can they be fully ap- 

 preciated. A bolting-cloth net drawn through 

 some of the pools will yield thousands in many 

 stages, and we can take eggs of the common star- 

 fish and watch their growth in tumblers of water. 

 At first the egg seems nothing but a tiny round 

 globule of jelly, but soon a dent or depression 

 appears on one side, which becomes deeper and 

 deeper until it extends to the centre of the egg- 

 mass. It is as if we should take a round ball of 

 putty and gradually press our finger into it. This 

 pressed-in sac is a kind of primitive stomach and 

 the entrance is used as a mouth. After this fol- 

 lows a marvellous succession of changes, form 

 giving place to form, differing more in appear- 

 ance and structure from the five-armed starfish 

 than a caterpillar differs from a butterfly. 



For example, when about eight days old, 

 another mouth has formed and two series of deli- 

 cate cilia or swimming hairs wind around the 

 creature, by means of which it glides slowly 

 through the water. The photographs of a starfish 

 of this age show the stomach with its contents, a 

 dark rounded mass near the lower portion of the 



