Semicassis granulata granulata

Scotch bonnet
Five views of a shell of Semicassis granulata granulata
Two live individuals of Semicassis granulata undulata in Archi, Reggio Calabria, Italy
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Gastropoda
(unranked):	clade Caenogastropoda clade Hypsogastropoda clade Littorinimorpha
Superfamily:	Tonnoidea
Family:	Cassidae
Subfamily:	Cassinae
Genus:	Semicassis
Species:	S. granulata
Binomial name
Semicassis granulata (Born, 1778)
Synonyms
List of synonyms Buccinum granulatum Born, 1778 (original combination) Phalium granulatum (Von Born, 1778) Phalium granulatum granulatum (Von Born, 1778) Cassis plicata (Scopoli, 1786) Buccinum cicatricosum Gmelin, 1791 Buccinum gibbum (Gmelin, 1791) Buccinum globosum Gmelin, 1791 Buccinum undulatum Gmelin, 1791 Cassis undulatus (Gmelin, 1791) Phalium cicatricosum (Gmelin, 1791) Cassidea granulosa (Bruguière, 1792) Cassidea sulcosus Bruguière, 1792 Cassis cepa (Röding, 1798) Cassis globulus (Röding, 1798) Cassis malum (Röding, 1798) Cassis inflata (Shaw, 1811) Phalium inflata (Shaw, 1811) Buccinum inflatum (Shaw, 1811) Cassis abbreviatus (Lamarck, 1822) Cassis laevigata (Menke, 1828) Cassis minuta (Menke, 1829) Cassis lacteus Kiener, 1835 Cassis tessellata (Pfeiffer, 1840) Semicassis ventricosa (Mörch, 1852) Cassis monilifera (Guppy, 1866) Cassis sulcosus var. elongata Weinkauff, 1868 Cassis sulcosus var. varicosa Weinkauff, 1868 Cassis reclusa (Guppy, 1873) Cassis gmelini Locard, 1886 Cassis undulatus var. ghirma de Gregorio, 1886 Cassis undulatus var. ebla de Gregorio, 1886 Semicassis undulata var. levilabiata Paetel, 1888 Cassis calamistrata Locard, 1892 Cassis undulatus var. minima Pallary, 1900 Cassis undulatus var. syriaca Pallary, 1938 Phalium loxahatcheense (Petuch, 1994)

The Scotch bonnet, scientific name Semicassis granulata, is a medium-sized to large species of sea snail, a marine gastropod mollusk in the subfamily Cassinae, the helmet shells and bonnet shells. The common name "Scotch bonnet" alludes to the general outline and color pattern of the shell, which vaguely resemble a tam o' shanter, a traditional Scottish bonnet or cap. The shell is egg-shaped and fairly large, 2 to 4 inches (5 to 10 cm) in maximum dimension, with a regular pattern of yellow, orange or brown squarish spots. The surface sculpture of the shell is highly variable: the surface can be smooth and polished, have grooves, be granulated, or even be nodulose on the shoulder of the whorls.

This species lives intertidally and subtidally on sandy substrates, and is found primarily in the tropical and subtropical Western Atlantic Ocean, from North Carolina to Uruguay. It is the most common species in this subfamily in North America. A similar-appearing sea snail in the Mediterranean Sea and Northern Atlantic Ocean, Semicassis granulata undulata, is currently considered to be a subspecies. The exact taxonomy of this species has been unclear in the past: as well as the current combination Semicassis granulata, 38 other combinations and synonyms exist.

In the spring, the adult females of this species lay eggs in tower-shaped structures. The eggs hatch as veliger larvae, which can float in the plankton for up to 14 weeks before settling onto the seabed as tiny snails. Crabs are a predator of this sea snail. After the death of the snails, if the shells are still intact they are often used by hermit crabs.