Home > Northwest Shells & Marine Life > PNW Shells & Marine Life Photos > Gastropods >  Gastropods - Nassariidae, Fasciolariidae
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Click on photo to enlarge.  Scale line in photo equals 1cm unless otherwise specified.
* Species which are commonly encountered on the beach.

Nassarius fossatus Nassarius fossatus Nassarius fossatus Nassarius fossatus
       Yachats, OR                          Freshwater Bay, WA, subtidal                                              Monterey, CA, subtidal                               Ucluelet, BC
Nassarius fossatus (Gould, 1850)
Giant Western Nassa
intertidal to 18m          northern Mexico to southern Alaska          size to 50mm
This is sometimes found intertidally.  The shell has a beaded sculpture and may be orangish-tan to gray-brown.  The rim of the aperture is usually orange.  It prefers a mud/silt habitat.
(previous names - Caesia fossatus, Nassa fossata, Alectrion fossatus)

Nassarius fraterculus Nassarius fraterculus
                    Centennial Beach, Boundary Bay, BC              Centennial Beach, Boundary Bay, BC, intertidal
Nassarius fraterculus (Dunker, 1860)
Japanese Nassa
intertidal          northern Washington to southern BC; Japan          size to 15mm
This is an introduced species from Japan and is occasionally found in the areas where it was introduced.  It is similar to our native H. mendica.  This has slightly angled axial ribs and faint spiral grooves.
There may be light colored stripes on the shell and the aperture is usually yellowish with dark stripes.
(previous name - Hima fratercula, Nassa fraterculus)

Tritia obsoleta Tritia obsoleta Tritia obsoleta
      Crescent Beach, Boundary Bay, BC               Crescent Beach, Boundary Bay, BC, intertidal                       Willapa Bay, WA, intertidal
Tritia obsoleta (Say, 1822)
Black Dog Whelk
intertidal to shallow subtidal          central California to southern BC; Florida to southeast Canada          size to 30mm
This species was introduced from the east coast of North America.  It can be very common where it is introduced.  The shell is gray to black with a glossy black aperture.  The shell is often weathered looking.  The snails prefer a muddy habitat.
(previous names - Ilyanassa obsoleta, Nassarius obsoletus, Alectrion obsoleta, Desmondia obsoleta)

Nassarius mendicus Nassarius mendicus
                           Silverdale, WA                                       Birch Bay, WA, intertidal                          
Nassarius mendicus (Gould, 1849)
Western Lean Nassa *
intertidal to 75m          northern Mexico to northern Alaska          size to 22mm
This is commonly found intertidally.  The shell is usually gray to brown but may also be striped with white.  It has spiral cords and straight axial ribs which can give it a somewhat beaded appearance.  These may also be worn down to muted sculpture.  The Nassa snails are scavengers.
(synonyms - Hima mendica, Alectrion mendicus, Nassarius cooperi, Nassarius indisputabilus)

Fusinus harfordii (Stearns, 1871)
Harford's Spindle
subtidal          size to 52mm
northern California to BC
This shell has spiral ridges and a thick periostracum.  The live animal is bright orange.

Fusinus harfordii
Raft Cove, Vancouver Is., BC

Olivella biplicata Olivella biplicata
                      Yachats, OR                                                          Yachats, OR, intertidal
Olivella baetica Olivella baetica
                         off Neah Bay, WA                                                             West Seattle, WA, subtidal
Olivella baetica Carpenter, 1864
Baetic Olive
intertidal to 60m          northern Mexico to northern Alaska          size to 27mm
This is rarely found intertidally in our area.  The shell is variably colored in shades of brown and is frequently patterned with zig-zag lines or splotches.  The shoulders usually have darker lines and the shell is glossy.  It prefers a muddy to silty habitat and is often buried in the sediment.
(synonyms - Callianax baetica, Olivella diegensis, Olivella intorta, Olivella mexicana, Olivella porteri, Olivella pedrona)


Family Nassariidae, Fasciolariidae

 & Olividae


Olivella pycna
off Neah Bay, WA

Olivella pycna S.S. Berry, 1935
Zigzag Olive
intertidal          northern Mexico to northern BC          size to 15mm
This is very infrequently found north of Oregon.  It is more squat than the Baetic Olive.  This one is also distinguished by its distinct wavy lines on a pale background.  The shell is glossy.  
(synonyms - Callianax pycna, Olivella pedroana)

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This page last revised: 5-25-2019

Olivella biplicata
Whiskey Creek Beach, WA
Olivella biplicata (Sowerby, 1825)
Purple Olive *
intertidal to 50m          northern Mexico to southern Alaska          size to 35mm
This is commonly found intertidally in some areas, usually open coastal beaches.  The shell may be brown to purplish in color with the occasional white or yellowish one found.  The aperture and bottom fold are white.  The shell width can vary for its height.  At low tide look for raised trails in the sand to find this species.  The coastal native peoples commonly used olives for necklaces and decoration and it is still highly regarded by the Makah Nation in Washington.
(synonyms - Callianax biplicata, Olivella angelana, Olivella lapillus, Olivella fucana, Olivella parva)