Molluscs of Southern California

(Click on images or names to open). *, Introduced species; +, Listed species. Squared background is 1/4 inch squares.

Photographed and compiled by Peter J. Bryant (
Department of Developmental and Cell Biology, University of California, Irvine, CA 92697
and some guests  

Bivalvia List of Newport Bay Bivalves
Cardiidae (Cockles) Chamidae Galeommatidae Limidae Lyonsiidae

Pacific eggcockle,
Laevicardium substriatum

Pacific Jewelbox,
Pseudochama exogyra

Internally-shelled clam, Chlamydoconcha orcutti

Hemphill Fileclam,
Limaria hemphilli

California Lyonsia,
Lyonsia californica

Pacific Gaper Clam,
Tresus nuttallii
Mytilidae (Mussels). Distinguishing Zebra and Quagga Mussels

* Quagga Mussel,
Dreissena rostriformis bugensis

* Ribbed Mussel,
Geukensia demissa

* Asian date mussel,
Musculista senhousia

California Mussel,
Mytilus californianus

* Mediterranean Mussel,
Mytilus galloprovincialis
Ostreidae (Oysters)      

* Pacific Oyster,
Crassostrea gigas

Olympia Oyster,
Ostrea lurida
Pectinidae (Scallops) Petricolidae Pholadidae (Piddocks)

Speckled Scallop,
Argopecten ventricosa

Giant Rock Scallop,
Crassadoma gigantea

Kelp Scallop,
Leptopecten latiauratus

Hearty Petricolid,
Petricola carditoides (?)

Rough Piddock,
Zirfaea pilbryi
Semelidae (Semeles) Solecurtidae

* Asian Semele,
Theora lubrica

Clipped semele,
Semele decisa

Neighbor Tagelus,
Tagelus affinis

California Jack-knife Clam,
Tagelus californianus

Lesser Tagelus,
Tagelus subteres
Tellinidae Ungulinidae      

Bent-nosed Clam,
Macoma nasuta

Orb Diplodon,
Diplodonta orbella

California Venus,
Chione californiensis

Pacific Littleneck,
Leukoma staminea

* Japanese Littleneck,
Venerupis philippinarum

California Butter Clam,
Saxidomus nuttalli

Two-spotted Octopus,
Octopus bimaculoides

Octopus, Octopus sp.
Archaeopulmonata Notaspidea      
Ellobiidae Tylodinidae      

Salt Marsh Snail,
Melampus olivaceus

Yellow Umbrella Slug,
Tylodina fungina
Aeolid Nudibranchs, distinguished from other nudibranchs by their possession of cerata containing cnidosacs.
"The aeolid cnidosac is one of the most remarkable examples of recycling in the animal kingdom. These animals eat cnidarians and are then able to retain at least some of the stinging cells (nematocysts) from the cnidarian, in a functional state so that they are able to reuse them in their own defence" (Sea Slug Forum).
Aeolidiidae   Facelinidae Fionidae

Shaggy Mouse Nudibranch,
Aeolidia papillosa

Red-tentacled Spurilla,
Spurilla oliviae

Opalescent Sea Slug,
Hermissenda opalescens

Fiona nudibranch,
Fiona pinnata

White-crusted Aeolid,
Tenellia (=Cuthona) albocrusta

Bertsch's Aeolid,
Flabellina bertschi

Spanish Shawl,
Flabellina iodinea

Three-lined aeolid,
Flabellina trilineata

Red-gilled Nudibranch,
Flabellina verrucosa
Dorid Nudibranchs, recognised by the gill plume forming a cluster on the posterior part of the body.
Aegiridae Chromodorididae Corambidae

Salt-and-pepper Doris,
Aegires albopunctatus

California Blue Dorid,
Felimare californiensis

Porter's Chromodorid Nudibranch, Mexichromis porterae

Frost-spot Nudibranch,
Corambe pacifica

Steinberg's Corambe,
Corambe steinbergae
Dendrodorididae Dorididae Discodorididae

Salted Yellow Doris,
Doriopsilla albopunctata

Doriopsilla davebehrensi

San Diego Dorid (Ringed Nudibranch), Diaulula sandiegensis

Monterey sea-lemon,
Doris montereyensis

Sea Lemon (Noble Dorid),
Peltodoris nobilis
Goniodorididae Onchidorididae

* Atlantic Ancula,
Ancula gibbosa

Pacific Ancula,
Ancula pacifica

Angeles Okenia,
Okenia angelensis

Hopkin's Rose,
Okenia rosacea

Black-tipped Spiny Doris,
Acanthodoris rhodoceras

McDonald's Dorid,
Limacia mcdonaldi

Sorcerer's Nudibranch,
Polycera atra

Hedgpeth's dorid,
Polycera hedgpethi

Speckled Triopha,
Triopha maculata


Dironidae Dotidae Nassariidae

Branched Dendronotus, Dendronotus venustus

Painted Dirona,
Dirona picta

Hammerhead Doto,
Doto amyra

British Columbia Doto,
Doto columbiana

Nassa Mud Snail,
Nassarius sp.
Tethydidae Zephyrinidae      

Hooded Nudibranch,
Melibe leonina

Cockscomb Nudibranch,
Janolus barbarensi
Acteonidae Aglajidae Aplysiidae

Striped Barrel Snail,
Rictaxis punctocaelatus

Striped Sea Hare,
Navanax inermis

California Sea Hare,
Aplysia californica

California Black Sea Hare,
Aplysia vaccaria

Eelgrass Sea Hare,
Phyllaplysia taylori
Bullidae Haminoeidae Limapontiidae Plakobranchidae

Gould's Bubble Snail,
Bulla gouldiana

Blister Glassy-bubble,
Haminoea vesicula

Enteromorpha-eating Sapsucker, Aplysiopsis enteromorphae

Brown-streak Stiliger,
Stiliger fuscovittatus

Hedgpeth's sea hare,
Elysia hedgpethi
Patellogastropoda Classification of Southern California Limpets

Volcano Limpet,
Fissurella volcano

Giant Keyhole Limpet,
Megathura crenulata

Rough Limpet,
Collisella scabra

Southern Finger Limpet,
Lottia austrodigitalis

Owl Limpet,
Lottia gigantea

File Limpet,
Lottia limatula

Coffee Bean Snail,
Pseudopusula californiana

Solander's Trivia,
Pusula solandri
Sorbeoconcha (=Caenogastropoda)
Atlantidae (Sea Snails) Buccinidae (Whelks) Conidae Calyptraeidae (slipper and cup-and-saucer snails)

Sea Snail,
Atlanta californiensis

Kellet's whelk,
Kelletia kelletii

California Cone Snail,
Conus californicus

(Larva) Pacific Half-slippersnail, Crepipatella lingulata

Spiny cup-and-saucer snail, Crucibulum spinosum
Cypraeidae Hydrobiidae Littorinidae

Slipper Limpet, Crepidula sp.

Chestnut Cowrie,
Cypraea spadicea

New Zealand Mud Snail, Potamopyrgus antipodarum

Checkered Periwinkle,
Littorina scutulata

Gray Littorine,
Littorina planaxis

Angular Unicorn,
Acanthinucella spirata

Gem Murex,
Maxwellia gemma

Emarginate Dog Winkle,
Nucella emarginata

Festive Murex,
Pteropurpura festiva
Potamididae Pterotracheidae Vermetidae    

California Horn Snail,
Cerithidea californica

Firoloida desmarestia

Scaly Worm Shell,
Serpulorbis squamigerus
Ischnochitonidae Lepidochitonidae Mopaliidae    

Conspicuous Chiton,
Stenoplax conspicua

Southern Spiny Chiton,
Nuttallina fluxa

Mossy Chiton,
Mopalia muscosa
Pulmonata (Land snails) Order Thecosomata
Helicidae Subulinidae Xantonychidae Desmopteridae

European Garden Snail,
Cornu aspersum

Spanish Snail,
Otala lactea

Decollate Snail,
Rumina decollata

Southern California Shoulderband, Helminthoglypta tudiculata

Sea Butterfly,
Desmopterus pacificus

+ Black Abalone,
Haliotis cracherodii

Threaded Abalone,
Haliotis kamtschatkana assimilis

Green Abalone,
Haliotis fulgens

Red Abalone,
Haliotis rufescens
Trochidae Turbinidae  

Smooth Brown Turban (Norris' Top Shell), Norrisia norrisi

Black Turban,
Tegula funebralis

Speckled Turban,
Tegula gallina

Wavy Top Turban,
Astraea undosa
Unidentified larvae

Veliger larva

Veliger larva

Limpet Veliger

Veliger larva

Veliger larva

Unidentified egg mass