EAST COAST MARINE SHELLS 



95 



often crenulated; plate dish-shaped with 

 puckered edge. Diameter 32 mm. 



This species will either excavate 

 a cavity for adherence or else secrete a 

 shell-like support corresponding to the 

 operculum. Range 0-189 fathoms. 



PI. 36, Fig. 7 



North Carolina to Texas; West Indies 



GENUS CALYPTRAEA Lamarck 1799 



Shell conical; apex posterior; half 

 cup-like appendage upon posterior side and 

 fastened to apex, open in front. Exterior 

 surface roughened or cancellated. 



CALYPTRAEA CENTRALIS Conrad. Shell very 

 small, thin, rounded, spire well elevated; 

 growth lines rough, white. Breadth 5 mm. 

 Depth range 1-52 fathoms. 



This little shell lives in the shal- 

 low water of Tarpon Bay, Sanibel, Florida. 



PI. 36, Fig. 9 



North Carolina to Gulf of Mexico; 



West Indies 



GENUS CRUCIBULUM Sch\imacher 1817 

 (CRUCIBLE SHELLS) 



Internal process of shell cup- 

 shaped with margin entire and attached at 

 one side of shell. 



CRUCIBULUM STRIATUM Say. Shell oval, con- 

 vex, with many slightly elevated, equal, 

 equidistant radiating lines; summit in- 

 clining toward the left side; inner process 

 attached to shorter side of the shell. 

 Length 1 inch. Range 3-189 fathoms. 

 PI. 36, Fig. 8 

 PI. 69, Figs. 27, 28 

 Nova Scotia to Florida Keys 



CRUCIBULUM AURICULA Gmelin. The typical 

 C. auricula is depressed and with fine ra- 

 diating lines upon the outer surface. Di- 

 ameter 1 inch or more. 



In Florida this species lives in 

 fairly deep water off shore and rarely if 

 ever has been found upon the beaches. In 

 the West Indies it occurs in much shallow- 

 er water and is frequently collected upon 

 the shore. The typical shell and its vari- 

 eties may easily be collected in the Plio- 

 cene fossil beds of Florida. Depth range 

 25-100 fathoms. 



PI. 59, Fig. 7 



Florida and the West Indies 



ing) 



(liv- 



CRUCIBULUM AURICULA IMBRICATUM Sowerby. 

 Like the preceding but with fine radiating 

 ribs upon the ribs. Occurs in the Caloosa- 

 hatchie fossil beds of Florida. 



Pacific coast from Lower California 



to Panama (living) 



CRUCIBULUM AURICULA SPINOSUM Sowerby. Shell 

 with radiating riblets, these provided 

 with tubular spines or tubercles. It oc- 

 curs in various tertiary beds of the south- 

 ern states. 



PI. 55, Fig. 4 



Monterey, California to Panama 



(living) 



CRUCIBULUM AURICULA COSTATUM Say. Radiat- 

 ing ribs strong but without fine sculpture 

 upon them. 



West Indies (living) 



Family Crepldulidae 



Shell oval, boat-shaped, spire im- 

 perfect; cavity partially divided within by 

 a horizontal partition. 



GENUS CREPIDULA Lamarck 1799 

 (QUARTER DECK, SLIPPER SHELL) 



CREPIDULA FORNICATA Linne. Boat Shell. 

 Shell obliquely oval, apex turned to one 

 side, generally close to margin of aper- 

 ture; epidermis yellowish; diaphragm white, 

 occupying about one-half of opening, one 

 side marked by a distinct line, the other 

 compressed against wall and united to it; 

 free edge of diaphragm waving, one-half ex- 

 tending beyond the remainder. Length 32mm. 

 Animal shown on PI. 68, Fig. 16. 



PI. 36, Fig. 5 



PI. 69, Figs. 23, 24 



Prince Edward Island to Texas; West 



Indies 

 CREPIDULA GLAUCA Say. Gray Slipper. Shell 

 of a glaucous or grayish-green color, 

 freckled with dots of a lighter color; apex 

 pointed, projecting and central; interior 

 dark brown or mottled, diaphragm white, mar- 

 gin yellowish. Length 14 mm. 



Common on the ocean shore of Rhode 

 I sland . 



