Morddyn:
5 Gastropod anatomy. Juvenile Buccinum undatum crawling on underside of inverted petri dish. Holes for escape of trapped air.
Morddyn:
6 Gastropod anatomy. Unrestrained Peringia ulvae turning from lying with shell aperture facing up. Head and yellowish hooked penis exposed for a few seconds during the turn.
Morddyn:
7 Gastropod anatomy. Male Peringia ulvae restrained by plasticine. Large penis visible protruding from shell behind head.
Morddyn:
8 Gastropod anatomy. This design of clothes peg has three points where shells may be gripped, and it has no metal parts to rust. Central peg painted black to prevent colour reflection in photography.
Morddyn:
9 Gastropod anatomy. Male Littorina fabalis, restrained by clothes peg (hidden by editing).