above; namely, for food. But in this instance their 

 selective mechanism seems not to function so well ; 

 for in dissecting one of these burrowers, we will 

 find in its stomach numerous sand-grains along 

 with the diatoms and other one-celled plants it 

 has swallowed. Whether the habit of burrowing 

 has modified their structure, or whether their 

 structure inclines them to bury themselves, is a 

 matter I will leave to the evolutionist; at any rate 

 they admirably overcome the handicap of an awk- 

 ward form in boring for their food. A worm, a no- 

 toriously soft-bodied creature, manages this thing 

 because of its linear shape; the serpent-star with 

 its radial arms accomplishes the same end by its 

 armor and its greater strength. 



Presently an arm is pushed out of the oozy silt, 

 just beyond the circle of my light. I catch its gaudy 

 pattern, nevertheless, and watch it for a moment 

 as its writhing form explores the adjacent region. 

 Then with a sudden movement I flash the full in- 

 tensity of the focused beam directly upon it. There 

 is a pause in its groping; then slowly it retracts and 

 disappears. This hide-and-seek game we play for 

 a while when I decide to repeat another experi- 

 ment. 



[73] 



