Common Egg Cowrie, Egg Snail
Phylum: Mollusca, Class: Gastropoda, Order: Littorinimorpha, Family: Ovulidae, Genus: Ovula, Species: Ovula ovum · Ovulidae (Allied Cowries or False Cowries) · Gastropod (univalve); glossy, globose/egg-shaped with extended terminals
Species
Ovula ovum
Shell Type
Gastropod (univalve); glossy, globose/egg-shaped with extended terminals
Family
Ovulidae (Allied Cowries or False Cowries)
Size
Approximately 7-9 cm (2.8-3.5 inches). This is consistent with the mature size for this species, which can reach up to 12 cm.
Color & Pattern
Dorsum is a striking, pure milky white with a high porcelain-like gloss. The interior (aperture) is a contrasting deep reddish-purple or chocolate brown. This specific specimen appears to have some natural minor surface spotting/staining from sand or organic matter.
Rarity
Common; frequently found in reef environments and widely available in the shell trade.
Habitat
Tropical shallow waters, typically found on or near soft corals (Alcyonacea), particularly Sarcophyton and Sinularia species, which serve as their food source.
Geographic Range
Indo-Pacific region, extending from East Africa and the Red Sea to the waters of Japan, Northern Australia, and out to the Central Pacific islands.
Description
An iconic shell known for its smooth, heavy, and extremely glossy white exterior that resembles a bird's egg. The shell is pyriform (pear-shaped) and inflated, with a long narrow aperture running the length of the underside. Unlike true cowries, the teeth on the labrum are less pronounced, and the mantle of the living animal is jet black with tiny white spots, which provides a stark contrast to the white shell it produces.
Key Features
Pure white glossy exterior; deep purple or brown interior; smooth pyriform shape; lack of dorsal markings; rounded extremities (terminals).
Collector Value
Low to Moderate ($5 - $20 USD). While beautiful and essential for a representative collection, their abundance makes them very affordable. Larger specimens over 10cm or those with exceptional lusters command higher prices.
Condition Notes
Good condition. The lustrous enamel is mostly intact, though there is some light surface dulling and minor brownish staining/accretions on the dorsum common in beach-found specimens. No major chips are visible on the terminals or lip.
Interesting Facts
Despite the white shell, the living animal has a spectacular velvety black mantle. They are termed 'false cowries' because they belong to the family Ovulidae rather than Cypraeidae. Historically, they have been used in many Pacific cultures as canoe ornaments and symbols of status or fertility.
Ecological Role
Specialized predators of soft corals; they are an important part of the reef ecosystem's biodiversity. They are not currently considered endangered, but their health is tied to the health of coral reef systems.
Similar Species
Calpurnus verrucosus (smaller with purple tips and a dorsal ridge); Ovula costellata (smaller with a pink ish interior).
Beach Finding Tips
Best found by snorkeling or diving near soft coral reefs during the night when the animals are most active. Empty shells occasionally wash up on reef-adjacent beaches after storms.