Doheney Beach, CA
Hornby Island, BC, subtidal
species in this order have a shell, and are commonly referred to as
Bubble Shells. A few only have vestigial shells which are hidden
inside the mantle.
Rictaxis punctocaelatus (Carpenter, 1864)
Striped Barrel Shell
to 100m northern Mexico to
southermost Alaska size to 20mm
This is infrequently found intertidally in the northwest. It lives on sand and glides just
underneath the surface of the sediment, usually just below eelgrass beds.
(previous name - Tornatella punctocaelata)
Retusidae Saltspring Island, BCRetusa obtusa (Montagu, 1803)Arctic Barrel-Bubble
intertidal to 300m shell size to 10mm
southern BC to Alaska; north Atlantic
Burrows in mud or muddy sand just within a few centimeters of the surface
off Grebe Islets, BC
Acteocina eximia (Baird, 1863)Pleatless Barrel-Bubble
intertidal to subtidal on sand and mud
shell size to 13mm
central California to central Alaska
(synonyms - Acteocina culcitella intermedia, Bullina eximia)
Aglajidae Birch Bay State Park, WA, intertidal
Aglaja ocelligera (Bergh, 1894)Spotted Aglajavery shallow subtidal to 20m on mud bottoms size to 20mmsouthern California to southern AlaskaIt has a vestigial internal shell. This is a small species and while it is
normally subtidal, it is possible to find it on a very low tide near
the water's edge which is where this one was photographed.
(previous name - Doridium ocelligerum)
This page last revised: 6-14-2019
west coast WA
Haminoea virescens (Sowerby, 1833)Green Bubble Shellintertidal Panama to Alaska size to 18mm
This is found only on rocky, open coast habitat.
Tornatinidae Tunstal Bay, BC
Acteocina culcitella (Gould, 1853)Western Barrel-Bubble
intertidal to 46m on sand and mud
shell size to 22mm
northern Mexico to central Alaska
(previous name - Cylichnella culcitella, Bulla culcitella)
Diaphanidae Rich Passage, WA, subtidal
Diaphana californica Dall, 1919California Diaphanaintertidal to shallow subtidal size to 5mmnorthern Mexico to northern WashingtonThis
is rarely found intertidally, partly due to its small size. The
shell is extremely thin and is similar in shape to the other bubble
shells, but with a flat apex. The animal is white.
in and near Rich Passage, WA, subtidal Gastropteron pacificum Bergh, 1894Pacific Stomach Wingintertidal to 425m size to 40mmnorthern Mexico to northern Alaska; GalapagosThis is infrequently found intertidally. This species may be readily seen when it is swimming. When buried in the sediment, it is a small lump in the mud.
(For more insight into this creature, see Ron Shimek's Blog posting of August 8, 2011.)
Rich Passage, WA, subtidalMelanochlamys diomedea (Bergh, 1893)Diomedes' Aglaja
intertidal to113m size to15mm
southern California to Alaska
It has a vestigial internal shell. It is very similar in appearance to Aglaja ocelligera, but without the white spots. It is light cream with brown and black mottling which can completely hide the cream color.
(synonyms - Aglaja diomedea, Aglaja nana, Aglaja ezoensis)
Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are the most commonly encountered nudibranchs on the beach.
Nudibranchs and other Sea Slugs