Trichuris trichiura

Alga in feces (unstained, low power). This object, known as a "Beaver body," is Psorospermium haeckelli, a stage of an alga that occurs in the tissues of crayfish (mudbugs). It sometimes is confused with helminth eggs when found in the feces of individuals who have recently eaten crayfish. They usually measure 135 to 155 µm long by 40 to 45 µm wide.