Cuthona nana, L.8mm. Cerata extend forward of rhinophores in adults. Dark cerata reported to result from feeding on female, rather than male, Hydractinia. LWS (on rock; not on Hermit crab). Orkney, Scotland. August 1976. det. T.E.Thompson.

Submitted by Ian Smith on Tue, 29/03/2011 19:51
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I.F. Smith

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Length 8mm. Note that cerata extend in front of rhinophores.
On rock on reef exposed to very strong currents, LWS, Orkney, Scotland. August 1976.
 Hydractina echinata occurs in separate male and female colonies. Female H. echinata are darker than males, so the C. nana feeding on them are darker than those on male colonies. This may account for the brownish colour of this specimen, or it may have been caused by a period of starvation which causes a loss of pink.