c 28 3 
1 am aware that this fliell contradifts the cha- 
ra&er I have given of the genus ; the hinge is ^ 
the eflential character of the recent fhells of the 
oyfter and fcallop ; but as the hinge cannot be 
always feen in foffil ones, it is placed here from 
its agreeing in habit with fome recent fpepies of 
fcallops which have equal valves* 
FIG* XXXIX 
A fingle fjat valve, marked with a few con* 
centric Jlrics i ears equal. 
Found in a flaty loopa at the lipie-ftone quar? 
ry near the Crefcent* 
' 
ammonia. 
