Book review: Spirals in Time - on seashells' ancient allure

When I was very young, a relative gave me a beautiful triton shell. Knobby and pale-rose on the outside, as pink as a kitten's mouth on the inside, the shell was a palm-sized wonder to my four-year-old self. I wanted badly to know how did the sound of the ocean get inside it? How did it become such a beautiful colour? What made it?

I eventually learned that a living thing called a mollusc made my triton - a thing that looked like the contents of a handkerchief, sure, but a thing that was also part of a distinguished, diverse family whose lineage on earth stretches back more than 500 million years.

English marine biologist Helen Scales delivers accessible answers to those kinds of questions in her book, Spirals in Time. It's a history and catalogue not just of what those little animals do, but what humans do with them.

For thousands of years, Scales notes, people have buried their notable dead with shells, worn shells on cords as jewellery, included their likenesses in artwork and used them as currency. Archaeologists found a shell collection in Pompeii's ash-covered ruins.

Scales introduces readers to the world's most prolific shell collector, Hugh Cuming, who amassed 83,000 shells by the time he died in 1865. "What is astonishing, though, is how universally shells have come to hold great meaning. Far from being just pretty things to look at, shells have been embraced as powerful emblems of sex and power, of birth and of death," Scales notes.

Scales dives deeply into the natural history of molluscs and the surprisingly complex things they do. Her explanation of the complicated and glorious process by which an organism makes a shell, and then adorns it with colours and patterns, is riveting.