84 Life Beneath the Waves. 



time, he had again covered himself with 

 pebbles ; and so completely was he hidden 

 beneath them, that if he had not crawled 

 up the side of the aquarium with his load, 

 I should have had some difficulty in dis- 

 covering his whereabouts. 



Occasionally the Sea-urchin will add the 

 adornment of a piece of seaweed to that of 

 the small stones, and I was much amused 

 one day to see him moving slowly along 

 with half a mussel shell on his back, 

 (which mussel I had opened, and placed in 

 the aquarium as food for its inmates), and 

 in the half shell sat a tiny crab as com- 

 fortably as possible, tearing off bits of the 

 mussel with its claws, and stowing them 

 away in its mouth, as complacently as if a 

 ride on the back of a Sea-urchin were its 

 usual custom at dinner time. 



The shell of the Echinus appears, at first 



