"In her memoir of living among the Bushmen, The Old Way: A Story of the First People, my friend Liz lovingly invokes an image first coined by evolutionary biologist Richard Dawkins: "You are standing beside your mother, holding her hand. She is holding her mother's hand, who is holding her mother's hand. . . . " Eventually the line stretches three hundred miles long and goes back five million years, and the clasping hand of the ancestor looks like that of a chimpanzee. I loved picturing one of Octavia's arms stretching out to meet one of her mother's arms, and one of her mother's mother's arms, and her mother's mother's mother's. . . . Suckered, elastic arms, reaching back through time: an octopus chorus line stretching not just hundreds, but many thousands of miles long. Back past the Cenozoic, the time when our ancestors descended from the trees; back past the Mesozoic, when dinosaurs ruled the land; back past the Permian and the rise of the ancestors of the mammals; back, past the Carboniferous's coal-forming swamp forests; back past the Devonian, when amphibians emerged from the water; back past the Silurian, when plants first took root on land--all the way to the Ordovician, to a time before the advent of wings or knees or lungs, before the fishes had bony jaws, before blood pumped from a multichambered heart. More than 500 million years ago, the tides would have been stronger, the days shorter, the year longer, and the air too high in carbon dioxide for mammals or birds to breathe. All the earth's continents huddled in the Southern Hemisphere. And yet still, the arm of Octavia's ancestor, sensitive, suckered, and supple, would have been recognizable as one of an octopus."