Gastropods

Click on photo to enlarge. Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.

Davenport, CA California, subtidal Calliostoma comparison

Calliostoma canaliculatum (Lightfoot, 1786)
Channelled Topsnail
intertidal to 25m northern Mexico to central Alaska size to 35mm
This is rarely found at an extreme low tide and is more often seen by divers. It lives on large kelp species. Its
coloration is very similar to the very common C. ligatum, but can be distinquished by its sharp-edged profile.
(synonym - Calliostoma doliarum)

offshore WA coast Barkley Sound, BC, subtidal Partridge Banks, Puget Sound, WA

Calliostoma variegatum (Carpenter, 1864)
Variable Topsnail
intertidal to 182m northern Mexico to southern Alaska size to 38mm
This is rarely found at an extreme low tide and is more often seen by divers. The shell may be very pale to brightly
ringed with brown spots. It may be found around pink branching hydrocorals and bryozoans.

Tofino, BC Marrowstone Island, WA, intertidal Anacortes, WA, intertidal Whidbey Island, subtidal, spawning

Calliostoma ligatum (Gould, 1849)
Blue Topsnail *
intertidal to 30m southern California to central Alaska size to 30mm
This is common intertidally. It can be a dull gray-brown color to blue-white with reddish rings. It is frequently covered with algae. Young shells can easily be confused with Margarites pupillus, but this shell does not have an open umbilicus like the margarite. When the surface of the shell
erodes away, it reveals a blue color.
(synonym - Calliostoma costata)

Victoria, BC Washington, subtidal Barkley Sound, BC, subtidal

Calliostoma annulatum (Lightfoot, 1786)
Purple-Ring Topsnail
intertidal to 42m southern California to central Alaska size to 30mm
This is rarely found at an extreme low tide and is more often seen by divers. Locally it is one of our most colorful shells.
The distinctive purple rings identify this shell, although they can be very faded. The animal is a bright orange color with darker patches.
It feeds mainly on hydroids.

Akoya platinum (Dall, 1890)
Silvery Topsnail
subtidal, 75-700m size to 32mm
southern California to southern Alaska
This is a rare species to find. The shell appears smooth with only faint spiral ridges.

Family Calliostomatidae