Cup-and-Saucer Snail (also known as the Spiny Slipper Shell)
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Calyptraeidae, Genus: Crucibulum, Species: Crucibulum striatum · Calyptraeidae (Slipper snail and cup-and-saucer snail family) · Gastropod (univalve) whole shell with a conical or cap-shaped spiral form featuring an internal cup-like septum.
Species
Crucibulum striatum
Shell Type
Gastropod (univalve) whole shell with a conical or cap-shaped spiral form featuring an internal cup-like septum.
Family
Calyptraeidae (Slipper snail and cup-and-saucer snail family)
Size
Approximately 1 inch in diameter, which is typical for an adult specimen of this species. Adults generally range from 0.75 to 1.5 inches.
Color & Pattern
Exterior exhibits a muted grayish-brown to pinkish-purple hue with rough radial ribs. The interior is porcelain white with a distinctive white internal appendage shaped like a half-cup attached to the apex.
Rarity
Common, though intact specimens with the fragile internal cup fully preserved are less frequently found pristine on sandy beaches.
Habitat
Found in shallow to moderately deep subtidal marine waters, attaching itself firmly to hard substrates such as rocks, shells, stones, and dead bivalve valves.
Geographic Range
Western Atlantic Ocean, ranging from Nova Scotia and the Gulf of St. Lawrence down to Florida and the Gulf of Mexico.
Description
A charming and unique conical shell resembling a miniature inverted hat or volcano. The exterior features prominent, coarse radial ribs and growth lines radiating from an off-center apex. The defining feature is the internal porcelain-like cup or shelf, which is half-attached to the interior wall, serving as a support for the animal's internal organs.
Key Features
Conical, cap-like shape with radial sculpture and the unmistakable internal half-cup structure (septum) fused to the interior apex.
Collector Value
Low to moderate commercial value. While not expensive, they are prized by specialist collectors for their unique internal anatomy and geometric form.
Condition Notes
Good condition. The apex is slightly worn, and the outer surface shows natural marine weathering, but the delicate internal cup structure is remarkably intact.
Interesting Facts
Like many members of the family Calyptraeidae, cup-and-saucer snails are protandric hermaphrodites, meaning they begin their lives as males and later transform into females as they grow larger.
Ecological Role
Suspension feeders that filter phytoplankton and organic particles from the water column, playing an important role in benthic nutrient cycling.
Similar Species
Crucibulum auritum and other slipper shells in the genus Crepidula, which lack the distinct enclosed cup structure and instead feature a flat internal deck.
Beach Finding Tips
Look among shell drift lines on gravelly or shelly beaches, or inspect discarded large bivalve shells where these limpets commonly make their homes.