Thursday, June 7, 2007

Bruised Nassa,Giant Bittersweet and Lettered Olive

Bruised nassa- Nassarius vibex (Say) is a small shell (about 1/2") with a rough surface. It has a coarsely beaded surface with equal spiral and axial ribs, resulting in about 12 ridges. It has a smooth inner lip with prominent parietal shield. It has a thick and toothed outer lip. It has a grayish brown exterior with a prominent cream-colored shield. It found in shallow-water sand flats on sound and ocean beaches. A scavenger, it also has been observed feeding on eggs of marine worms. (information from "Seashells of North Carolina by Porter and Houser North Carolina Sea Grant College Program")

Giant Bittersweet, Glycymeris americana (DeFrance)
Grows to 4 inches, is round and a somewhat flat shell. Indistinct broad radial ribs sculptured with radiating scratches. It has a central beak and a long curved hinge with 19-24 teeth. It's color is a grayish tan exterior and mottled with yellowish borwn. It lives offshore in depths of 75 feet near and south of the Capefear river. (Information from "Seashells of North Carolina by Porter and Houser - North Carolina Sea Grant College Program")

Lettered olive, Oliva sayana (Ravenel) A smooth, shiny, cylindrical shell with a short spire. Narrow aperture extending almost length of shell, continuing around the bottom and ending in a notch on the other side. No operculum. It's cream or grayish exterior with reddish brown zigzag markings and lives in near-shore waters on shallow sand flats near inlets. It's commonly washed onto ocean beaches. A carnivore, it captures bivalves and small crustaceans with its foot and takes them below the sand surface to digest. Its presence is sometimes detected at very low tides by the trails it leaves when it crawls below the surface on semi-exposed sand flats.
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Marsh Periwinkle and Florida Melampus

This is a Marsh Periwinkle, Littorina irrorata.
5/8-1 1/2" (1.6-3.8cm) high. These were found on the high tide line on Ocean Isle Beach, NC. Broadly ovate, think, sharply pointed except when eroded; Whorls smooth, slightly convex. Columellar area and inside of outer lip whitish, the latter with a dark margin and dark brown deep within. Habitat: on rocks intertidally. In Europe, this very common and abundant shell is still gathered and eaten by many people. Information from "The Audubon Society Field Guide to North American Seashells pages 401-2.

The Florida Melampus, Detracia floridana is found at the high tide line. (5/8 ") Small, cone-shaped shell with a short, blunt spire. Long, narrow aperture with front end expanded. Color: Light to dark brown, occasionally with three to four darker-colored spiral bands. Also called a salt-marsh snail, this family has a primitive lung in place of gills and breathes air. The snail eats decaying plant matter but is believed to get its nutrients from the bacteria that live on decaying matter. Information found in"Seashells of North Carolina - NC Sea Grant College Program Porter and Houser".
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