^S Pearls. 



largest shell in existence, and it is occasionally 

 used for church-fonts : a huge pair, used as benitiers, 

 in the church of St. Sulpice in Paris, were presented 

 to Francis I. by the Republic of Venice. The 

 clam is a bi-valve found buried up to the lips, 

 hinge downwards, in coral reef: it breathes with 

 siphons, but requires space to open its shell a few 

 inches. Instances are recorded of men having 

 stepped between the open valves, which have closed 

 immediately with the powerful adductor muscles, 

 and such an accident is almost certain death, either 

 by loss of blood, or by the rising tide. 



Concretionary bodies commonly called Pearls, 

 but usually lacking the characteristic nacreous lustre, 

 are occasionally found associated with the shells of 

 certain gasteropods or univalves. They are of a 

 pink or rosy colour in the great conch shell of 

 the West Indies (S trombus gigas), which is one of 

 the very largest known shells. Somewhat similar 

 pinkish concretions are yielded by another univalve 

 known as the Turbinella Scolymus. 



Yellow Pearls from other shells are often 

 offered for sale in the East, where they are much 

 valued, but they are not yet appreciated in England. 

 They evidently come from a porcellanous shell 

 probably a gasteropod. .The natives of the Sooloo 



