Time is not a river: It's a choice ...Returning from a rescue expedition to the Devonian period, 360 million years in Earth's past, Coel Rydin, Merola Tsverin, and their robot companions discover that their mission has failed, at least partially. The monster Glyph had concocted a virus to change the lobe-finned fishes from evolving into the familiar line of four-limbed animals known to Earth and instead sprout six-limbed chimera. And Rydin's antibody...