746 DR. J. E. GRAY ON THE CALYPTR^.ID^. [JuilC 27, 



The smooth specimens sometimes have costated or cancellated 

 tips, and the converse. The surfaces of the different varieties and 

 the form of the shells are often altered by the form and surface of 

 the body to which they are attached. 



2. CrUCIBULUM AURICULATUM. 



Patella auriculata, Chemn. Dispotea auriculata. 

 Shell white, brown-spotted, and varied with distant regular sharp- 

 edged radiating ribs ; inner surface white or brownish. 

 Hab. West Indies ; St. Thomas's ; Cumana. 

 The Atlantic form of the preceding. 



3. Crucibxjlum violaceum, Carpenter, 



Shell white, brown-varied, with close regular round-topped ra- 

 diating ribs ; inner surface purplish. 

 Hob. Ceylon. 



4. Crucibulum maculatum. 

 Calyptrcea maculata, Brod. 



Shell white, solid, brown-spotted, with very close, round-topped, 

 nearly regular radiating ribs. 

 Hab. 1 



5. Crucibulum tubiferum. 



Dispotea tubifera, Say. 



Crucibulum spinosum, Sowerby. 



C. hispidum, Brod. 



Chenu, Man. f. 2333, 2334. 



Shell solid, brown, or brown white-rayed ; closely radiately striated, 

 and often with more or less close radiating ribs furnished with 

 tubular spines. 



Hab. Peru ; Gulf of California. 



Tribe VII. The shell conical, subcircular ; apex central, acute; 

 cavity regular, conical, with a folded plate at the top of the 

 cavity, free from the sides ; the foot of the animal secreting a 

 lower calcareous plate. Calyptrina. 



Calyptra, Humphrey; Adams. 



Calyptrcea, Lamk. 



Calyptrus, Mont. 



Mitrularia, Schum. 



Calyptria, Lithedaphus, et Litholepas, Owen. 



* Shell entire, without spines. 



1. Calyptra corrugata, Adams; Chenu, Man. f. 2326, 2328. 



Calyptrcea corrugata, Brod. 



Yar. smaller. C. layardi. Reeve. ? C. umbo. Reeve. 



