199 



MULTIVALVES. 



This class according to Linnaeus, contains 

 three genera. The generic character is chiefly 

 determined by the number of valves and their 

 position. 



Genus. PROLA.S* Plural, Pholades. 



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 A*ND 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 re- 

 semble lace; in others, they are coarser, and 

 approaching to small basket work. The Pholades 



* Plate X. figure 8. 



