Cowries
left - Trivia arctica, right - Trivia monacha
Trivia arctica: Elie (NO460006), 15/10/2001, approx 9mm across
Trivia monacha: above - Gower Peninsula (SS505865), 05/05/1999, 11mm across; below - Arisaig (NM655900), 13mm across
© Sarah Longrigg