CALYPTRAEIDAE 171 



Variable in shape, rarely quite flat, sometimes high and arched. They may 

 be corrugated if the individual has lived attached to a scallop or ribbed 

 mussel. A common littoral species. When collecting on the west coast of 

 Florida, do not confuse with C. maculosa. C. fornicata has been introduced 

 to the West Coast of the United States. 



Crepidula maculosa Conrad Spotted Slipper-shell 



AVest Coast of Florida to Vera Cruz, Mexico. 



Resembling C. fornicata, but often spotted with small, mauve-brown 

 blotches and sometimes streaked. The edge of the deck is straight or only 

 very slightly convex. There is an oval muscle scar on the inside of the shell 

 just below and in front of the right anterior edge of the deck and the main 

 shell. The young are very much like southern forms of C. convexa Say. 



Crepidula convexa Say Convex Slipper-shell 



Plate 2 in 



Massachusetts to Florida, Texas and the West Indies. 



^ to ^ inch in size, usually highly arched and colored a dark reddish to 

 purplish brown. Interior, including the deck, chestnut to bluish brown. 

 Some specimens may be spotted. The edge of the deck is almost straight. 

 There is a small muscle scar inside the main shell on the right side just under 

 the outer corner of the deck (see also maculosa). Some specimens are thick 

 and heavy, others quite fragile, the latter type found attached to other shells. 

 Common just offshore down to 1 16 fathoms. 



The form glauca Say is H inch long, thin-shelled, usually dark-brown 

 or translucent-tan, and with a white deck. It is found in over-crowded col- 

 onies on eel-grass where specimens become long and narrow. C. acuta Lea 

 is this form also. 



Crepidula aculeata Gmelin Spiny Slipper-shell 



Plate 2iq 



North Carolina to Florida, Texas and the West Indies. 



/4 to I inch in size, similar to foniicata, but characterized by its rough, 

 spinose exterior, thinner and flatter shell and by its irregular edges. Color 

 whitish, although often heavily mottled with reddish brown. The exterior 

 is sometimes stained green by algal growths. A common species found at- 

 tached to stones, mangroves and other shells. Occasionally dredged. 



Crepidula onyx Sowerby Onyx Slipper-shell 



Plate 2of 



Monterey, California, to Peru. 



