Scotch Bonnet
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Cassidae, Genus: Semicassis, Species: Semicassis granulata · Cassidae (Helmet and Bonnet family) · Gastropod, whole shell, spiral shape with a prominent elongated aperture and flared outer lip.
Species
Semicassis granulata
Shell Type
Gastropod, whole shell, spiral shape with a prominent elongated aperture and flared outer lip.
Family
Cassidae (Helmet and Bonnet family)
Size
Approximately 3 inches in length, which is average for this species. Adults typically range from 2 to 4.5 inches.
Color & Pattern
Cream to pale beige base color adorned with distinct rows of reddish-brown, square-shaped or zigzag markings. The interior of the aperture is a smooth, glossy cream with a thickened outer lip.
Rarity
Common to Uncommon, highly prized by beachcombers though frequently found in offshore dredge material or washed ashore after storms.
Habitat
Found in shallow subtidal to moderately deep offshore waters, typically living on sandy bottoms, offshore sand bars, and near coral reefs or rocky areas.
Geographic Range
Western Atlantic Ocean, ranging from North Carolina down through the Gulf of Mexico, the Caribbean Sea, and as far south as Brazil.
Description
An elegant, sturdy oval shell featuring a low spire and a large, wide body whorl decorated with spiral cords and granular beads. The exterior showcases striking, checkered or zigzag reddish-brown patterns over a pale background. The aperture is wide and elongated, terminating in a short canal, with a heavily thickened, flaring outer lip that features tiny tooth-like denticles on the inner edge.
Key Features
Low rounded spire, granular sculpted spiral cords, prominent thickened outer lip with inner denticles, and distinctive checkered or zigzag brown markings on a pale background.
Collector Value
Moderately high collector value, especially for specimens with exceptional color patterns, intact lips, and larger sizes. Typically valued between $5 to $25 depending on condition and locality.
Condition Notes
Fine condition with good retention of original color pattern and a glossy aperture, though showing minor natural wear consistent with drift specimens.
Interesting Facts
The Scotch Bonnet is the official state shell of North Carolina. The living animal uses its broad foot to glide across sand and preys primarily on sea urchins and sand dollars by boring holes into their tests.
Ecological Role
Acts as an important carnivorous predator in benthic marine ecosystems, helping to regulate sea urchin populations. Empty shells frequently serve as mobile homes for hermit crabs.
Similar Species
Cassis tuberosa (King Helmet) and Phalium bisulcatum, but can be distinguished from helmets by its smaller size, finer granular texture, and lighter build.
Beach Finding Tips
Best found on outer barrier island beaches following heavy winter storms or strong offshore winds, particularly during low tide while walking along the wrack line.