MONOaRAPH OF THE FAMILY 



CALYPTRiEDiE. 



Testa patelliformis, adhserens, subtus appendice furcata 

 vel calyculata, aut lamina semispirali aut septiformi mimita. 

 Limpet-sbaped-sliells, having an internal plate or appendage 

 in place of the basal plate and columellar lip of spiral shells. 

 In Caltptea, as limited in this monograph, it is a sort of 

 forked projection from the apex. In Crucibulum, with some 

 variations, it is an oval cup projecting from the apex, but 

 attached by one side to the inner wall of the shell. In 

 Tegchita, it forms a spiral or semispiral base to the last 

 whorl ; and in Crepidula it is more or less septiform. We 

 accept this general arrangement (from Reeve) as the most 

 convenient, although, through intervening forms, the genera, 

 excepting the first, cannot be very exactly defined. 



Genus CALYPTRA. 



Molluscum interdum laminam basalem extraneam formans. 

 Testa albida, epidermide tenui induta; appendice columellari 

 projecta, fornicata, bifurcata. — The forked projection re- 

 sembles the half of a narrow split funnel, and serves the 

 purpose of an internal support in place of the usual spiral 

 column. 



Sjpecies. 



1. EQUESTRis, f. 1,2, Linnceus. — T. elevato-conica, liris 

 scabriusculis profundis, ad marginem prominentibus sculpta, 

 margine crenato; appendice magna; lamina basali solida, 



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