Photo of a belted crayfish, also called Big River crayfish.

    Belted Crayfish (Big River Crayfish)

    Faxonius harrisonii (formerly Orconectes harrisonii)
    Bluefer

    Bluefer (Purpleshell)

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

    Bryozoans (Moss Animals)

    Freshwater species in the phylum Bryozoa
    Photograph of Ebonyshell freshwater mussel shell exterior view

    Ebonyshell

    Fusconaia ebena
    exclamation mark

    Endangered

    elephant's ear

    Elephantear

    Elliptio crassidens
    exclamation mark

    Endangered

    Photo of a freckled crayfish.

    Freckled Crayfish

    Cambarus maculatus
    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 a golden crayfish viewed through the surface of creek water.

    Golden Crayfish

    Faxonius luteus (formerly Orconectes luteus)
    Photo of a gray-speckled crayfish.

    Gray-Speckled Crayfish

    Faxonius palmeri (formerly Orconectes palmeri)
    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
    Photo of a longpincered crayfish.

    Longpincered Crayfish

    Faxonius longidigitus (formerly Orconectes longidigitus)
    pistolgrip

    Pistolgrip (Buckhorn)

    Tritogonia verrucosa
    pond mussel

    Pond Mussel

    Ligumia subrostrata
    Photo of a red swamp crawfish or crayfish.

    Red Swamp Crawfish

    Procambarus clarkii
    Photo of a ringed crayfish.

    Ringed Crayfish

    Faxonius neglectus (formerly Orconectes neglectus)
    Photo of a saddleback crayfish.

    Saddleback Crayfish

    Faxonius medius (formerly Orconectes medius)
    Spectaclecase

    Spectaclecase

    Cumberlandia monodonta
    spike

    Spike (Ladyfinger)

    Elliptio dilatata
    Photo of a spothanded crayfish viewed through creekwater.

    Spothanded Crayfish

    Faxonius punctimanus (formerly Orconectes punctimanus)
    Photo of a St. Francis River crayfish.

    St. Francis River Crayfish

    Faxonius quadruncus (formerly Orconectes quadruncus)
    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 vernal crayfish.

    Vernal Crayfish

    Procambarus viaeviridus
    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
    Photo of a woodland crayfish.

    Woodland Crayfish

    Faxonius hylas (formerly Orconectes hylas)