Tongue Worms: Pentastomida - Physical Characteristics

As their common name suggests, many adult pentastomids (pen-tah-STOH-mids) have long, wormlike bodies in the shape of a tongue. They measure up to 5.9 inches (150 millimeters) in length. The head has a small mouth underneath with a hook on each side. The hooks can be withdrawn inside the head. Their long, fluid-filled bodies are ringed, but not segmented. The soft external skeleton (exoskeleton) is whitish or clear. Because they live inside their food and are surrounded by everything they need, tongue worms do not have or need circulatory, respiratory, or excretory systems. They move like a maggot (fly larva), inching along by contracting their muscles and shifting body fluids inside to force the body forward or backward. Adult females are much larger than males and are usually filled with hundreds of thousands to millions of eggs.