138 The Under-Water World 



during the rainy season. When the 

 drought comes the mangrove branches, 

 coated with oysters, hang five feet above 

 the water level. Each shell is attached 

 by its lower or deeper valve which con- 

 tains enough moisture to keep the 

 mollusc alive until the waters rise 

 again and cover it in about six months' 

 time. 



Related to the oysters are the Mussels 

 which clot every rock and harbour pile 

 and attach themselves by means of long 

 tough threads which they secrete. In 

 Pinna, a fan-mussel of our shores, these 

 anchor ropes are enormously elongated, 

 forming huge tufts of silky fibre several 

 feet in length from which gloves, socks, 

 scarves, etc., have been woven. Pearls 

 occur in certain kinds of oriental mussels 

 and the Chinese introduce little lead 

 images of Buddha between the shell and 

 the mantle of a common fresh-water 

 form. In due season these images be- 



