not forming extensive burrows are numerous others, 

 such as the wing shells, Vteria and Vinctada, the ark 

 shells, Area and Barbatia, the date mussel, !Modiolus, 

 and the scallop shells, Vecten and £ima. The jewel 

 box shell, Chama, and the so called reef oyster, Spon- 

 dylus are well known to collectors. The strange oyster 

 Ostrea frons with hook-like outgrowths from the shell 

 whereby it attaches itself, is often found on corals or 

 seafans. Trapped in the rock by growth of the living 

 coral around them are also found £ima and Vteria. 



Some of the sea worms similar to those commonly 

 used for bait are able to bore through the living rock 

 by means of powerful jaws. One of these, Eunice jucata, 

 has the peculiar habit of breaking off the hindmost part 

 of the body in which the eggs develop. This portion 

 leaves the burrow and swims to the surface of the water, 

 where the eggs are released by breakdown of the body 

 enclosing them. This happens at a certain phase of 

 the moon during midsummer, m the early morning and 

 the careful observer may see the surface of the ocean 

 above the reef literally alive with wriggling worms. In 

 the Pacific islands where a similar phenomenon takes 

 place, the Palolo worms, as they are called, are highly 

 esteemed as food. 



Some worms do not destroy the rock but use their 

 burrows for protection. They are lined with a hard 

 porcelain like material and the head of the living worm, 

 which projects into the surrounding water when un- 

 disturbed looks like a beautifully colored flower. A 

 slight movement or shadow, however, will cause retrac- 

 tion into the burrow so quickly that the movement is 

 undetectable. 



Sea anemones and seasquirts are frequently assoc- 



49 



