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This species has been observed on Reunion, Mayotte and Madagascar Islands

Order : Cephalaspidea Superfamily :  Haminoeidea Family : Haminoeidae Distribution : Indo-West Pacific Maximal size (shell) : 50 mm Abundance : Species characteristics : Body white, with a brownish headshield and translucent white area around the eyes and a black spot between them Adult sp (like our specimen) with white patches on the edges of the parapodia and black and white markings along the posterior edge of the mantle, shell brown broad with dark striations throughout Juvenil sp with brown longitudinal lines on the shell
	Showing species characteristics...	Photo Alain-Benoît Rassat Madagascar, Olaf, 18 m, 6 April 2016, during the night, size : 40 mm

See more about : Sightening and mating periods

Remarks :

Identification confirmed by Raymond Huet and Nathalie Yonow
    Synonymous (according worms):
              - Atys cymbulus Montfort, 1810                                  - Bulla naucum Linnaeus, 1758
              - Atys ferruginosa (A. Adams, 1850)                          - Haminoea ferruginosa (A. Adams, 1850)  
              - Bulla ferruginosa A. Adams, 1850                                  

Bibliographic data :

Atys naucum is the large inflated white bubble shell found in tropical waters. The brown colour of the shell of living animals is a thin periostracum covering the shell. It soons dries and flakes off when the animal dies.
    All species of Atys are herbivores. Under the sand during the day or cruising on the surface at night

References :

Mollusques de l'île de la Réunion. Collection Jay: Atys naucum
   SeaSlug Forum Atys naucum
   Philippine Sea Slug Atys naucum

Publications :

Linnaeus, C. (1758) Systema Naturae , Ed. 10. Vol.1.

Other photos of Atys naucum :

Maurice Jay Réunion, Shell ref : 291 Collection Maurice Jay Ovoid almost spherical. Deep spiral grooves over the whole surface, sometimes absent in the middle part. White . Live in the sand of 10-20 m. Rare Maximum height 30.7 mm.

Remy Eudeline Mayotte, Sakouli lagoon, less 1 m, 16 November 2017

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