The Urban Pantheist

As I scooped up this ragworm (Phylum Annelida, Class Polychaeta, Family Nereidae) in my fingers, I remembered seeing similar worms when I was a child. One particular time one was dragged up onto to the damp sand and poked with a stick. In response the worm everted a pair of fearsome jaws from its head, each bearing a sharp-looking tooth. It turns out those teeth are as hard as human teeth--they're made of a protein matrix studded with ions of the metal zinc.