Calma glaucoides
Alder & Hancock, 1854

Family: Calmidae


Northeastern Atlantic from Norway to western Mediterranean.


UPPER: Baie de Peyrefitte (near French/Spanish Mediterranean border), under stones in 4 m deep, in June, 2002. Approx 20 mm long. Photo: Patrick Heurtaux.
LOWER: radular ribbon with indiviudal teeth fused into a serrated ribbon. Scale bar = 1 micron. PHOTO: Gonçalo Calado.

This strange species appears to feed exclusively on the eggs of teleost fish. It grows to about 25mm but is seldom seen outside the fish egg masses it feeds on. The anus is absent, apparently because there is little waste in the highly nutritious food Calma feeds on.

See message from Gonçalo Calado below comparing Calma glaucoides which feeds on eggs of Lepadogaster lepadogaster, Lepadogaster purpurea, Lepadogaster candollei, Parablennius gattorugine and Parablennius pilicornis, with Calma gobioophaga Calado & Urgorri, 2002 which feeds on the spawn of Gobius niger,.

• Alder, J. & Hancock, A. (1854). Notice of some new species of British Nudibranchiata. Annals and Magazine of Natural History, 14(2): 102-105
• Calado, G. & V. Urgorri, 2002. A new species of Calma Alder & Hancock, 1855 (Gastropoda: Nudibranchia) with a review of the genus. Journal of Molluscan Studies, 68: 311-317.

Authorship details
Rudman, W.B., 1999 (September 15) Calma glaucoides Alder & Hancock, 1854. [In] Sea Slug Forum. Australian Museum, Sydney. Available from

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