King Helmet Snail
Cassis tuberosa
To 30cm

Shell light tan, often with reddish wavy, net pattern. Usually 7 to 8 dark bands on outer lip. Flattened lip around aperture forms a triangle.

Shallow sandy flats  from 0-35ft (0-11m). The King Helmet feeds on sea urchins at night, apparently detecting its prey by chemoreception. It generally bores a single hole into the urchin test (the urchin's external skeleon) by cutting out a disc with its radula.  All the internal tissue of the urchin except the gut contents is consumed. Afterwards, varying proportions of the spines and tube feet are eaten. 
Despite its toxic sharp spines, even the black sea urchin (Diadema antillarum) is attacked and eaten, which it actively pursues the urchin and appears to overwhelm it physically, despite the phalanx of spines that Diadema brings to bear on any point of attack. When feeding on an urchin, it uses its long proboscis to probe among the spines to reach the urchin's body. It  also everts its proboscis when it is broken from its shell, and then usually squirts a jet of clear fluid in different directions, while thrashing its proboscis. This saliva is toxic to numerous marine organisms and conceivably could be used offensively as well as defensively.

Life Cycle
Single sex and broadcast spawners. Embryos develop into planktonic trocophore larvae and later into juvenile planktonic veligers before becoming fully grown adults.
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
Be, S 30 Ech, Noct I F
King Helmet Snail