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
    giant floater

    Giant Floater

    Pygandon grandis
    Photo of a giant water bug

    Giant Water Bugs

    Species in the genera Abedus, Belostoma, and Lethocerus
    Venomous Icon

    Venomous

    Photo of several prosobranch pond snails crawling on a rock.

    Gilled Aquatic Snails (Prosobranch Pond Snails)

    Over 20 Missouri species in former subclass Prosobranchia
    Photo of hellgrammite

    Hellgrammite

    Corydalus cornutus
    Photo of a horsehair worm in an aquarium

    Horsehair Worms

    About 350 species scientifically described.
    No photo available

    Hydras

    Various species in the genus Hydra
    Photo of a leech

    Leeches

    Various species in the subclass Hirudinea
    lilliput

    Lilliput

    Toxolasma parvus
    pistolgrip

    Pistolgrip (Buckhorn)

    Tritogonia verrucosa
    pond mussel

    Pond Mussel

    Ligumia subrostrata
    Spectaclecase

    Spectaclecase

    Cumberlandia monodonta
    spike

    Spike (Ladyfinger)

    Elliptio dilatata
    threeridge

    Threeridge

    Amblema plicata
    Photo of a pink planarian on a rock.

    Turbellarians (Planarians; Free-Living Flatworms)

    Species in genera Dugesia, Planaria, etc.
    Photo of a water scorpion, genus Ranatra, captured in a jar of pond water.

    Water Scorpions

    Ranatra spp. and Nepa apiculata
    white heelsplitter

    White Heelsplitter

    Lasmigona complanata
    Photo of a White River crawfish.

    White River Crawfish

    Procambarus acutus