Submerged unsedated male L. fabalis restrained with aperture facing up.
Long vermiform filament (1) measuring 42% of penis length (species range 30% to 60%), and single row of 14 large mamilliform glands (2) along 58% of penis length (species range 3 to 17 glands along 40% to 70% of penis) .
On this species the glands are usually visible on live unsedated specimens as they are large and protrude into view from the mesial face of the penis concealed against the body.
Shell height 12.5 mm. Llŷn, North Wales. September 2015.
Full account at: 02 Differentiation L. obtusata/L. fabalis

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