Locality: Off Gnejna Bay, 80-100 metres, Malta, Mediterranean, July 1997, muddy sand with decaying dead algae.. Length: 7mm. Photographer: C. Mifsud.
This cephalaspidean is ditinguished by the texture of its heavily punctate external shell. Nothing is known of its anatomy. It is possibly a philinid but could well be a scaphandrid.
It again emphasises the work that needs to be done on Mediterranean cephalaspids. Although Monterosato (1884) suggested the shell of this animal may be external, this photo is the first evidence I know of, showing that it is indeed external. To my knowledge we know nothing of its internal anatomy. Monterosato (1884) created the genus Johania for Bulla vestita Philippi, 1844, based on its peculiar punctate shell pattern. This species was subsequently synonymised with Bulla retifer Forbes, 1844 but I don't know whether the date has been properly checked to see whether Forbes name should have priority.
Monterosato, T. (1884) Nomenclatura generica e specifica di alcune Conchiglie Mediterranee. Palermo, Virzi. 1-152.
Philippi, R. A. (1844) Fauna Molluscorum viventium et in tellure tertiaria fossilium regni utriusque Sicilae. [Enumeratio molluscorum Sicilae cum viventium tum in tellure tertiaria fossilium quae in itinere sua observavit. Vol 2.] Halle, E. Anton. 1-304.
Pilsbry, H.A. (1896) Manual of Conchology; Structural and Systematic with Illustrations of the Species. [Ed: G.W.Tryon] Vol. 16, 251 pp, Pls 1-71.
Pruvot-Fol, A. (1954) Mollusques Opisthobranches. Faune de France, Paris 58: 1-460, Pl.1.
Rudman, W.B., 2007 (March 16) Johania retifera (Forbes, 1844). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/johareti