92 
Linn. which I have ventured to consider it, though I have 
not seen the hinge. Should any of our friends get pos- 
session of a specimen showing that part, I shall be glad of 
such information as will be decisive, and will give notice 
accordingly. I have only seen casts. 1 believe there are 
several species of this Genus found in a fossil state in this 
country. 
