Pacific Moon Snail (Alternate: Lewis's Moon Snail)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Naticidae, Genus: Neverita, Species: N. lewisii · Naticidae (Moon Snail family) · Gastropod (Univalve); this specimen is a large body-whorl fragment. The shape is globular and spiral in life, though this piece shows the characteristic curving curvature of the outer shell.
Species
Neverita lewisii (Confidence: 85%)
Shell Type
Gastropod (Univalve); this specimen is a large body-whorl fragment. The shape is globular and spiral in life, though this piece shows the characteristic curving curvature of the outer shell.
Family
Naticidae (Moon Snail family)
Size
The fragment appears to be roughly 3-4 inches across. Given the curvature, the original whole shell likely measured 5-6 inches in diameter, which is typical for a mature adult of this species.
Color & Pattern
The exterior exhibits a creamy off-white to yellowish-tan base. It shows visible growth lines (striae) and some brownish-orange staining, likely from minerals in the sediment or weathering. The interior surface (visible on the edges) is smooth and slightly polished. The periostracum (outer skin) is mostly worn away.
Rarity
Common (as a species), though whole specimens are much more prized than fragments. Fragments are very common on beaches like Coronado following high surf.
Habitat
Intertidal to shallow subtidal zones, typically found in sandy or muddy bottoms where it can burrow to hunt prey. It is a strictly marine species.
Geographic Range
Eastern Pacific Ocean, ranging from British Columbia, Canada, down to northern Baja California, Mexico. Common along the California coast including San Diego/Coronado.
Description
This is a significant fragment of the body whorl of a large moon snail. The shell is remarkably thick and heavy, designed to withstand the pressure of burrowing and coastal surf. The exterior features fine, concentric growth rings that follow the spiral growth of the snail. The curvature indicates a large, globose shape characteristic of the Naticidae family.
Key Features
Heavy, thick calcium carbonate structure; smooth internal nacreous layer; distinct curved fracture lines along the growth axis; lack of external ribs or spines; large size characteristic of the Western Coast moon snails.
Collector Value
Minimal financial value ($0-$2) due to its fragmented state. Complete, high-quality specimens of this size can fetch $10-$30. It holds educational value for demonstrating shell thickness and growth patterns.
Condition Notes
Poor to Fair. This is a partial fragment (beach wear) rather than a complete specimen. It shows significant erosion, a missing apex (spire), and a broken aperture. Collector grade: Beach/Study piece.
Interesting Facts
Moon snails are predatory 'drills' that use a radula to bore perfectly circular holes into the shells of clams and other bivalves. They also create a unique 'sand collar' egg case, which looks like a discarded piece of rubber or plastic on the beach but is actually made of sand and mucus containing thousands of eggs.
Ecological Role
Active carnivore and apex predator of the sandy benthos. They control bivalve populations. Their discarded shells, when whole, provide essential housing for large hermit crabs.
Similar Species
Euspira lewisii (often synonymized) and Neverita recluziana (Recluz's Moon Snail). The latter is smaller and has a heavy callus covering the umbilical area, whereas N. lewisii is the largest moon snail in the world.
Beach Finding Tips
On Coronado Beach, look for these after winter storms or during extreme low tides (minus tides). While fragments are common, whole shells are often found partially buried in the sand near the low-tide line.
Notes
Coronado beach