21 Margarites helicinus. Height 4.1mm, diameter 5.2mm. Orkney, Scotland. May 2017. Leg. S.Taylor.

21 Margarites helicinus. Height 4.1mm, diameter 5.2mm. Orkney, Scotland. May 2017. Leg. S.Taylor.

Cilia on the dorsal surface of the left neck-lobe beat to create an inhalant respiratory current (1) to the large bipectinate ctenidium within the mantle cavity. Cilia on the dorsal surface of the right neck-lobe create an exhalant current (2) for respiratory water, ova or sperm, and faeces.

marinvert.senckenberg.science/image-browse/