Janolus cristatus
(delle Chiaje, 1841)

Suborder: ARMININA
Family: Zephyrinidae


Northeastern Atlantic from Norway to Morocco, and western Mediterranean.


Oosterschelde, Goese Sas, the Netherlands. Depth 5 meters. PHOTO: René Lipmann.

Grows to75mm in length. Feeds on erect bryozoans such as Bugula. Although species of Janolus look very like aeolids, there is no close relationship. In this species, with transparent cerata, a digestive gland duct can be clearly seen running to the ceratal tip where it divides into a number of terminal branches. Unlike aeolids, there are no terminal cnidosacs, and the cerata form a fringe around the anterior edge of the mantle. The anus also opens in the dorsal midline in the posterior half of the body, where in aeolids it opens in the right anterior quarter, usually on the side of the body.

• Delle Chiaje, S. (1841). Descrizione e notomia degli animali invertebrati della Sicilia citeriore osservati vivi negli anni 1822-1830, Napoli, 7: pls. 86-173 (Nudibranchia pls. 88, 89, 100, 106, 178). Text in vol. 8, p. 6 (1844)

Authorship details
Rudman, W.B., 1999 (September 2) Janolus cristatus (delle Chiaje, 1841). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/janocris

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