To begin, you must first determine the location of an earthworm's front end. The saddle or clitellum, a fleshy ring around its middle that sits closer to its head-end, is the best method to determine. The common earthworm may survive having its tail cut off below the saddle because you'll be missing most of its major organs. Still, it'll never be the same again. So, if at all feasible, use caution when holding your lawn spade.