Left: proximate (inner) face, visible if mantle cut open.
Right: distal (outer) face; side seen through mantle when animal extracted from shell.

1: anus. 2: rectum. 3-6: pallial oviduct. 3: opening of oviduct 4: jelly gland (parallel septa faintly visible in left view). 5: albumen gland. 6: capsule gland.

A clearly developed pallial oviduct such as this, without any sign of shelled embryos, is diagnostic for differentiating L. arcana females from L. saxatilis sensu stricto females, which have a brood pouch with embryos in place of the oviduct.
But take care not to class specimens without developed oviduct or brood pouch as L. arcana because of the absence of embryos; they could be either. Males in breeding condition have prominent penes, but out of condition, the penis may be small or missing and the prostate gland, in the same position as oviduct, might be mistaken for a L. arcana oviduct.

No full account yet of this species.
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