---
title: Horned Helmet (Cassis cornuta)
scientific_name: Cassis cornuta
common_name: Horned Helmet
taxon: Prosobranchia
published: 2026-08-11T15:43:16.959Z
updated: 2026-08-11T16:57:21.896Z
tags: Horned Helmet, Cassis cornuta, Prosobranchia, Red Sea, Marine Life, Diving
url: https://redseacreatures.com/taxon/invertebrate/molluscs/prosobranchia/horned-helmet
---

# Horned Helmet (*Cassis cornuta*)

## Quick facts

- **Group:** Prosobranchia (*Prosobranchia*)
- **Size:** up to 40 cm
- **Depth:** 1-30 m
- **Diet:** Carnivore
- **Activity:** Nocturnal
- **Rarity:** Rare
- **Habitat:** Sand flats and seagrass near reef, buried by day
- **Reproduction:** Egg layer, Gonochoric

## How to recognise it

- enormous heavy shell with a broad glossy orange-cream shield underneath
- row of blunt knobs like horns around the shoulder
- females much larger and heavier than males
- shell to 40 cm

The biggest snail most divers here will ever see: a slab of shell up to 40 cm (16 in), knobbed like a crown around the shoulder and finished underneath with a broad glossy shield in orange and cream. Females grow far larger than males, and a full-sized one takes two hands to lift, which is the main reason to admire it and put it back.

It eats sea urchins. The snail engulfs one with its foot, secretes acid from a gland to soften the test, drills through it with the radula and consumes the animal from the inside, spines and all. Where these snails have been fished out, urchin numbers climb and reefs are grazed harder - one large predator missing from a sand flat is felt across the whole system.

That shield underneath is why it has been fished out over much of its range. It is the classic cameo shell: carvers cut through the white outer layer into the orange beneath to leave a raised figure, a trade running from Roman times through Victorian Europe to modern souvenir stalls. A live one on the sand is now a genuinely rare find in the Red Sea.

## Also known as

- **English:** horned helmet shell, giant helmet, horned helmet
- **German:** Gehörnte Helmschnecke, Große Sturmhaube
- **Japanese:** トウカムリ
- **Russian:** Кассис рогатый

## Scientific synonyms

- *Buccinum cornutum* Linnaeus, 1758
- *Cassis (Cassis) cornuta* (Linnaeus, 1758)
- *Cassis caputequinum* Röding, 1798
- *Cassis hamata* Röding, 1798
- *Cassis labiata* Dillwyn, 1817

## Range

Kenya, Madagascar, Mascarene Islands, Mozambique, Republic of Mauritius, South Africa, Tanzania

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*Source: [Red Sea Creatures](https://redseacreatures.com/taxon/invertebrate/molluscs/prosobranchia/horned-helmet)*
*Updated: August 11, 2026*