2 1 2 CALYPTR^lDiE. 



Shell conic, trochiforni, spiral ; summit central ; whorls convex, 

 plicate, not umbilicated ; aperture large, containing a spiral 

 transverse lamina, extending obliquely from the centre to the 

 outer margin of the shell. The animal has an oblong foot, 

 bilobed anteriorly. 



HALIOTIDEA, Swaiuson. Shell conic, spiral, the spire excentric, 

 whorls convex, smooth, umbilicated. /. dilatata, Sowb. (Ixvi, 26). 



Calyptr^a, Lam. 



Cup and saucer limpet. 



Syn. — Cemoria, Risso. Mitrella, Trochilina, Trelania, Pocu- 

 liua. Gray. Mitrularia, Schum. Lithedaphus, Owen. 



Distr. — Temperate and tropical ; world-wide. G. llartiniana, 

 Reeve (Ixvi, 21). 



Shell conical, more or less regular, with subcentral, subposte- 

 rior sharp apex ; aperture basal, with a central lamina, half cup- 

 shaped, attached to the apex and open in front. 



Animal with broad muzzle ; tentacles rather short, lanceolate ; 

 eyes on bulgings at the outer bases of the tentacles ; mantle- 

 margin simple, sides plain. 



Cruoibulum, Schum., 181*7. 



Syn. — Bicatillus,Bicoma, Swains. Siphopatella, Lesson. Tre- 

 lania, Neleta, Gray. 



Distr. — Temperate and tropical; world-wide. G. rudis, Brod. 

 (Ixvi, 28). 



Differs from Calyptrsea in the internal cup-shaped lamina, 

 which is entire and attached along a line on one side to the inner 

 wall of the shell. 



DTSPOT^A, Say. (Cal3qoeopsis, Lesson.) Cup-shaped lamina 

 adhering to the whole of one side. G. striata, Say (Ixvi, 29). 



CATILLINA, Gray. Oblong, conical, radiately ribbed ; the apex 

 acute, subcentral, recurved; nucleus regular, spiral; cavity 

 conical, with a broad trigonal cup on the left side under, but not 

 extending to the apex of the cavity, filled with a callous deposit 

 at the tip ; the part of the cup next to the inner surface of the 

 shell scarcely thickened and not raised up. Grucibidum conca- 

 merata, Rve. (Ixiv, 11). 



Crepidula, Lam. 



Etym. — Grepidula, a small sandal. 



Syn —Cr^qDta, Humph. Sandalium, Schum. Crepipatella, 

 Lesson (?). Tylacus, Lyroscapha, Conrad. 



Distr. — 50 sp. West Indies, Atlantic and Pacific Coasts of 

 N. America, Mediterranean, W. Africa, India, Australia. G. 

 Peruviana, Lara. (Ixv, 91). Fossil. Cretaceous — . 



Shell oval, limpet-like, with a posterior, generally lateral spiral 

 apex ; interior with a shell}^ lamina covering its posterior half. 



