Gray, speckled, translucent gelatinous blob cut in half to show structure

    Bryozoans (Moss Animals)

    Freshwater species in the phylum Bryozoa
    Monkey Face Mussel

    Freshwater Mussels

    Bivalve molluscs in order Unionoida
    Photo of a horsehair worm in an aquarium

    Horsehair Worms

    About 350 species scientifically described.
    Photo of a leech

    Leeches

    Various species in the subclass Hirudinea
    Photo of a red swamp crawfish or crayfish.

    Red Swamp Crawfish

    Procambarus clarkii
    Photo of a St. Francis River crayfish.

    St. Francis River Crayfish

    Faxonius quadruncus (formerly Orconectes quadruncus)
    Photo of a pink planarian on a rock.

    Turbellarians (Planarians; Free-Living Flatworms)

    Species in genera Dugesia, Planaria, etc.
    Photo of a White River crawfish.

    White River Crawfish

    Procambarus acutus