Eastern Musk Turtle (Stinkpot) (Sternotherus odoratus)
Above and below: A Musk Turtle, or Stinkpot, in Charles Co., Maryland (5/9/2009). A nice find by Mikey Lutmerding while we were covering the Nanjemoy area for the Charles Co. May Count. Its names refer to its habit of releasing a fowl odor from special glands when it feels threatened by potential predators.
Below: For comparison, here is the species I encounter much more regularly in Maryland, the Mud Turtle (Nanjemoy, 5/9/2009).