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Flatworms look like
Flatworms look like "flying carpets" as they glide through the water. (The Southeastern Regional Taxonomic Center, South Carolina Department of Natural Resources)

Flatworms are tiny, leaf-shaped worms that live among reefs, jetties and eelgrass meadows in the shallows of the middle and lower Chesapeake Bay.

Two species of flatworms can be found in the Chesapeake Bay:

  • Oyster flatworm, Stylochus ellipticus
  • Slender flatworm, Euplana gracilis


  • Flat, symmetrical, leaf-shaped body
  • The oyster flatworm is cream-colored and the slender flatworm is yellowish-gray
  • The oyster flatworm has a row of eyespots along the front of the body. The slender flatworm has eyespots in two rows along the head.
  • The oyster flatworm has short tentacles on its sides, while the slender flatworm does not have tentacles
  • Grow to a size smaller than a quarter


  • Live among reefs, piers, jetties and other hard surfaces in shallow waters
  • Also found in eelgrass meadows


  • Abundant throughout the middle and lower Chesapeake Bay


  • Major predators of barnacles, bryozoans and oyster spat
  • Hunts by waiting for its prey to open its valves to feed. Then the flatworm inserts its mouth into the open valves to feed on its prey’s interior parts.

Reproduction and Life Cycle:

  • Life cycle is not well known
  • Oyster flatworms have both male and female reproductive organs. But scientists aren’t sure whether a flatworm can fertilize its own eggs, or if eggs need to be cross-fertilized by another flatworm.

Other Facts:

  • Flatworms look like "flying carpets" as they glide through the water

  • Have you ever seen a flat, jelly-like blob hiding underneath a rock or shell near the Bay's shoreline? It may have been a flatworm!

Sources and Additional Information:

  • Life in the Chesapeake Bay by Alice Jane Lippson and Robert L. Lippson
  • Chesapeake Bay: Nature of the Estuary, A Field Guide by Christopher P. White

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