CALYPTRAEIDAE 169 



I % inches in diameter, Vs as high, obhquely ovate, fairly thin, and with 

 a small, hooked-over apex. Shell w^hite, covered by a soft, fuzzy, light-brown 

 periostracum. Interior glossy-white. A rather rare species found in 20 to 

 30 fathoms attached to Pecten diegensis. 



Family CALYPTRAEIDAE 

 Genus Calyptraea Lamarck 1799 



Calyptraea centralis Conrad Circular Cup-and-saucer 



Plate 21-0 



North Carolina to Texas and the West Indies. 



/4 to % inch in diameter, cap-shaped, with a circular base, and pure 

 white in color. Apex central, small, minutely coiled and glossy-white. The 

 shelly cup is attached to the inside of the shell and is flattish, arises near the 

 center of the shell and flares out to the edge. Its free side is thickened into a 

 columella-like, rounded edge. Commonly dredged in shallow water, espe- 

 cially off southeast Florida. Formerly known as C. candeana Orbigny. 



Calyptraea fastigiata Gould Pacific Chinese Hat 



Plate 20I 



Alaska to southern California. 



Ys to I inch in diameter, about H to % as high; the outline of the base 

 of the shell is perfectly circular, and the apex is at the center of the shell. 

 Interior glossy-white with the sinuate edge of the internal cup arising at the 

 apex of the shell as a thickened, twisted columella and ending in fragile at- 

 tachment near the edge of the shell. Young forms (C. contorta Cpr.) are 

 relatively higher-spired. Exterior chalky-white with a thin, brownish perios- 

 tracum. Dredged moderately commonly from lo to 75 fathoms. 



Genus Crucibulum Schumacher 18 17 

 Crucibulum auricula Gmelin West Indian Cup-and-saucer 



Plate 2 IS 



West Florida to the Lower Keys and West Indies. 



I inch in diameter, similar to C. striatum, but the edges of the inner cup 

 are entirely free. The edges of the main shell are crenulated, the external 

 ribs are coarser, and the interior is sometimes pinkish. The outer surface may 

 show coarse diagonal ribs if the specimen has lived attached to a scallop or 

 other ribbed mollusk. Uncommonly dredged in shallow water and occasion- 

 ally washed ashore. 



