19 Rissoa membranacea.

19 Rissoa membranacea.

Behind the tentacles the dorsal colour of the snout continues on the body dorsally with a whitish, medial, longitudinal band (1) in the posterior half.
Within the mantle cavity is a short, grey-white ctenidium with relatively few short stout filaments (2). The respiratory inhalent current comes into the mantle cavity at the left of the head and has the water quality tested by the osphradium before reaching the ctenidium. Shell height 4.9mm. Orkney, Scotland. May 2017. Leg. S. Taylor.

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