CHAPTER XX: THE LUCINAS 



Family LuciNiOiE 



Shell circular, equivalve, with small, depressed beaks and 

 distinct lunule; hinge teeth, cardinals two, laterals two, or tooth- 

 less. Animal without siphons; foot very long, vermiform, hollow; 

 two or four gills, often modified into brood chambers, their tissues 

 occupied by eggs. A tropical family living in sandy mud, well 

 represented on our own warm coasts by shells handsomely sculp- 

 tured with ribs or lattice work. 



Genus LUCINA, Brug. 



Characters of the family. 



The Tiger Lucina (L. tigrina, Linn.) has^/me concentric 

 ridges crossing paired ridges that radiate from the beaks. The 

 valves are ventricose, solid and white. The long foot is folded 

 upon itself and concealed between the gills. Diameter, 3 

 inches. 



Habitat. — Florida to Texas. 



The Florida Lucina (L. Floridana, Conr.) is an exceedingly 

 abundant species on shallow, protected sand flats. The rough 

 surface is dingy white, the growth lines yellow. The minute 

 beaks point forward. Diameter, i inch. 



Habitat. — West coast of Florida and Keys. 



A deep water species, L. filosa, Stimps., is found all along 

 our Atlantic coast. It is overlaid with elegant growth ridges. 

 Diameter, 2 inches. 



L. Pennsylvanica, Linn., wears a wrinkled epidermis which 

 gives it a ribbed appearance and a yellow colour, though the 

 valves are white, and ridged only on the large lunule. The dis- 

 tinguishing characters are the diagonal furrows which bound 

 the posterior area, as angular ridges do in many species. Diam- 

 eter, 2 inches. 



Habitat. — Cape Hatteras, Florida coast, West Indies. 



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