Dissected penis from L. fabalis with shell height 9.5 mm.
Dissected penes have the advantage of being easily examined on both sides. The mesial face with mamilliform glands (1), is often held hidden against the body when alive, though the 3 to 17 glands on live L. fabalis are usually large enough to protrude into view.
The vermiform filament (2, distal portion of penis beyond glands) of L. fabalis is somewhat contracted in death, but still clearly different from the short triangular filament of L. obtusata despite being fixed in a contorted position in this image.
Swanage, Dorset, England. April 2016.
Full account at: 02 Differentiation L. obtusata/L. fabalis

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