194 MULTIVALES. 



MULTIVALVES. 



This class according to Linnaeus, contains 

 three genera. The generic character is chiefly 

 determined by the number of valves and their 

 position. 



GENUS. PHOLAS* 



STONE PIERCER. 



Generic character. Shell with two primary 

 valves gaping at both ends, and several smaller 

 accessory valves situated upon the hinge and 

 posterior slope ; hinge recurved, each valve has 

 a long tooth curved inwards. 



OBSERVATIONS ON THE SHELL AND ITS 

 INHABITANT. 



The shells of this genus are thin, fragile, and 

 usually either of a pure or dusky white, adorned 

 with beautiful minute fret work : the reticulations 

 in some species are so delicate and fine as to 

 resemble lace ; in others, they are coarser, and 

 approaching to small basket work. The Pho- 

 lades were ranked by Linnaeus among the mul- 

 tivalves, but by modern conchologists they are 

 generally placed with the bivalves. The two 



* Plate X. figure S. 



