Giant helmet
Cassis cornuta
- Usual depth5–10 m
- Water temperature20–30 °C
- Best monthsMay, July, and August
- How commonRare
Photo credit: (c) H. Zell, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
About this species
Cassis cornuta, common name the horned helmet, is a species of extremely large sea snail, a marine gastropod mollusc in the family Cassidae, the helmet shells and their allies.
Text from the Wikipedia article “Cassis cornuta”, licensed CC BY-SA 4.0. Read the article
Where and when
Where it has been recorded
Worldwide
Loading the map
Best months
Worldwide (open data)
- January: 38 records
- February: 23 records
- March: 27 records
- April: 34 records
- May: 43 records
- June: 30 records
- July: 43 records
- August: 39 records
- September: 30 records
- October: 33 records
- November: 36 records
- December: 30 records
Depth and water temperature
Depth
Mostly recorded at 5–10 m · Deepest record: 10 m
Water temperature
Recorded in surface water of 20–30 °C
Photos
(c) Didier Descouens, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist 
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist 
(c) Roger Rittmaster, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Min-Hsuan NI, some rights reserved (CC BY) · CC BY · iNaturalist 
(c) Jay Paroline, some rights reserved (CC BY) · CC BY · iNaturalist 
no rights reserved · CC0 1.0 · iNaturalist 
(c) Georgina Jones, some rights reserved (CC BY-SA) · CC BY-SA · iNaturalist
Names and classification
- English
- Giant helmet, Horned helmet, Horned helmet shell, giant helmet, horned helmet, horned helmet shell
Names in 2 more languages
- German
- Gehörnte Helmschnecke, Große Sturmhaube
- Japanese
- トウカムリ
Other scientific names: Buccinum cornutum, Cassis (Cassis) cornuta, Cassis caputequinum, Cassis hamata, Cassis labiata
Similar species
Atlantic casmariaCasmaria ponderosa
Sources and credits
Names and taxonomy: WoRMS (CC BY 4.0) and the GBIF Backbone (CC BY 4.0). Photos: iNaturalist observers, each under the licence shown (CC0, CC BY or CC BY-SA).
- Depth, temperature, months and maps: records from OBIS and GBIF under CC0 or CC BY.
- Descriptions: Wikipedia, licensed CC BY-SA, each linked to its article.
- Conservation status as published by GBIF (IUCN Red List).
- 160 open-data records from 1758 to 2012.
- Species data updated October 26, 2026.
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