Common Indo-West Pacific species.
Koumac, northern New Caledonia, October 1993. Animal 28mm long alive.
It is possible when more of the many tropical species are studied that they will be placed in other genera. At present most species are tropical and have heavy well-calcified shells. In most cases the true foot is short and the shell extends a considerable distance beyond its posterior end. The parapodial flaps, which are part of the foot, therefore only fold around the anterior end of the shell. The posterior flap of tissue which looks like part of the foot, is in fact an outgrowth from the mantle cavity. A similar "false posterior foot" is found in species of Haminoea.
•Helbling, G.S. (1779). Bulla cylindrica. In: Abhandlungen einer Privatgesellschaft in Böhmen zur Aufnahme der Mathematik, der väterlandischen Geschichte, und der Naturgeschichte, zum Druck befördert von Ignaz Edlen von Born. Prag, Vol 4, p. 122, Pl. ii, f.30,31.
Rudman, W.B., 1998 (December 18) Atys cylindrica (Helbling, 1779). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/atyscyli