Patterns in Space and Time

How seashells get their colour

Vittina waigiensis (Neritidae), a pseudopolymorphic species, having bets each way with their colour patterns. Philippines, Indonesia, New Guinea and the Solomon Islands. Own collection. © Bronwen Scott.

I gathered shells upon the sand,
Each shell a little perfect thing,
So frail, yet potent to withstand
The mountain-waves’ wild buffeting.

Edith Nesbit, Sea-Shells

No 18th century cabinet of curiosity was complete without a collection of shells. The finest came from tropical oceans: cones patterned with flags and…