Apparently widespread in temperate Australia, with records from sthn Western Australia, Victoria, Tasmania.
Upper: Rocky Cape, NW Tasmania, Australia, 4 m, 14 Oct 1984. AM C143617. Lower: Breakwater, Stanley, NW Tasmania, 6 Jan 1985. AM C144526. [lengths to follow] Photos: Bill Rudman.
Little is known about this species apart from its original description, based on 3 specimens from Western Australia. The animal is almost transparent, with the body organs showing through the skin. Fine red specks are scattered over the skin and slightly larger white glandular dots are also present. Sometimes the white can form larger clusters as on the rhinophore tips and and on the cerata. The animals usually have an overall pinkish tint which is accentuated when the branched digestive gland in the cerata is full of recently ingested cell contents from the red algae thay feed on. The body is quite slender and the cerata are arranged in two or more rows down each side [not one as in original description], and the cerata range in size from quite small to very large. In my experience, cerata are autotomised very easily, which could explain the differing accounts of ceratal arangement.
Jensen reports it feeding on a species of the red algae Griffithsia and describes the feeding process as: "[The algae has] cells that are often larger than the head of the animal. The emptied cell is completely deflated. When the animals are sucking, the cerata pulsate vigorously. The radula only 'rasps' for a few seconds, then very rapid sucking occurs..."
Jensen, K.R. (1993) Sacoglossa (Mollusca, Opisthobranchia) from Rottnest Island and central Western Australia. In: Proceedings of the 5th International marine Biological Workshop: The marine Flora and Fauna of Rottnest Island, Western Australia. (Eds: Wells, F.E; Walker, D.I.; Kirkman, H; Lethbridge, R) Western Australian Museum, Perth, 207-253.
Rudman, W.B., 2006 (July 14) Hermaea evelinemarcusae Jensen, 1993. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/hermevel