Scientific classification
Superdomain: Neomura
Domain: Eukaryota
(unranked): Opisthokonta
(unranked) Holozoa
(unranked) Filozoa
Kingdom: Animalia
Subkingdom: Eumetazoa
(unranked): Bilateria
(unranked): Protostomia
Superphylum: Lophotrochozoa
Phylum: Mollusca
Subphylum: Conchifera
Class: Gastropoda
Subclass: Orthogastropoda
Order: Littorinimorpha
Superfamily: Cypraeoidea
Family:Cypraeidae
Subfamily:Erosariinae
Genus:Nucleolaria
Species:N. granulata

22,1mm

Oahu, Hawaii

From my collection

via Flickr https://flic.kr/p/2iTtieq