Two radulae; anteriors on left of image.
The broad radula is of rhipodoglossan form, probably the most primitive type of gastropod radula (Fretter & Graham, 1962).
M. helicinus feeds by sweeping microphytes (diatoms etc) and detritus from the substrate with its widely fanned rhipidoglossan radula, ‘rhipidos’ (Greek) = fan, with a ‘whirlpool motion’ (Gwatkin, 1914).

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