Animal removed from shell, and black pigment (see 13 Velutina velutina. Shell height 10mm. ELWS. Gairloch, North-west Scotland. May 2019. Leg. D. McKay & S. Taylor. ) rubbed off translucent mantle.
1: mantle rim with thin, yellowish upper layer and thick, white lower layer.
2: left and right columellar muscles.
3: comb-like ctenidium (gill).
4: osphradium for testing water quality before it reaches the gill. In this species it has a structure similar to the ctenidium. Early workers misinterpreted it as a second smaller ctenidium (Jeffreys, 1867).
5: very extensive white hypobranchial gland lining the entire roof of the mantle cavity to the right of the ctenidium.
6: genital ducts.
7:rectum.
8: auricle of heart
9: ventricle of heart.
10: ovotestes.

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