Gastropods

Marsenina rhombica (Dall, 1871)
Marbled Lamellarid
intertidal to subtidal size to 40mm
northern Mexico to southern Alaska
This is rarely found. It is very difficult to spot against the compound tunicate on which it lives. The body of the animal blends in perfectly and the shell is barely visible.
(previous name - Lamellaria rhombica)

Marsenina stearnsii (Dall, 1871)
Stearn's Ear Shell
intertidal to 19m northern Mexico to central Alaska size to 20mm
This is rarely found. The pattern of spots on the animals body perfectly blends with the compound tunicates on which it lives. The empty shell looks identical to that of M. rhombica. They can only be identified by the living animal.
(previous name - Lamellaria stearnsii)

Port Townsend, WA, subtidal Pearse Islands, BC, subtidal

Marsenina zadei Behrens, Ornelas & Valdes, 2014
subtidal, at least 3-15m Monterey Co., CA to Pearse Islands, BC size to 15mm
This small species is found on an encrusting compound ascidian where it is well camouflaged. The mantle is off-white to tan to orange and is sprinkled with black specks. Some specimens exhibit a dark brown horseshoe mark and within this mark are tubercles. The shell is a translucent white and exhibits growth lines.

San Juan Islands, WA Petersburg, AK, intertidal

Cryptonatica affinis (Gmelin, 1791)
Arctic Moonsnail
Very low intertidal to subtidal northern Mexico to northern Alaska size to 25mm
This is rarely found intertidally. This animal has a calcareous operculum. The shell is virtually identical to C. aleutica. They can be differentiated by the live animal. In this species the body of the animal is pure white.
(synonyms - Natica affinis, Natica clausa, Cryptonatica clausa)

Limneria prolongata (Carpenter, 1864)
Smooth Velvet Snail
intertidal to 100m size to 22mm
central California to northern Alaska
This is infrequently found intertidally. It lives under rocks. The shell has a brown periostracum. The animal has a distinctive orange margin on the foot and banded markings on the mantle.
(previous name - Velutina prolongata)

San Juan Islands, WA Petersburg, AK, intertidal (very low tide)

Cryptonatica aleutica (Dall, 1919)
Aleutian Moonsnail
intertidal to 400m southern California to northern Alaska size to 60mm
This is infrequently found intertidally. The animal has a calcareous operculum. The body of the animal is covered with brown spots. This shell grows much larger than C. affinis.
(previous name - Natica aleutica)

Velutina velutina (O.F. Müller, 1776)
Spiral Velvet Snail
subtidal to 100m size to 20mm
central California to northern Alaska;
circumpolar, south to Maine & the Meditteranean
This species is infrequently found intertidally. The shell has spiral ridges under its thick brown periostracum. It is found on rocks near tunicates.
(synonyms - Velutina laevigata, Velutina plicatilis, Velutina sitkensis, Velutina cryptospira)

Calinaticina oldroydii (Dall, 1897)
Oldroyd's Fragile Moonsnail
subtidal to at least 200m size to 70mm
north Mexico to south BC
This species has a thin shell and generally a squat shape. It has a wide, deep umbilicus. The horny operculum is has light brown rays which indicate growth increments.
(previous name - Sigaretus oldroydii)

Euspira pallida (Broderip & Sowerby, 1829)
Pale Northern Moonsnail
intertidal to 500m size to 40mm
north Mexico to north Alaska; circumpolar
This is rarely found intertidally. The umbilicus is almost completely closed and it has a horny operculum. The living animal is translucent white in color.
(previous names - Polinices pallidus, Lunatia pallida)

Birch Bay State Park, WA Penrose Point State Park, WA, intertidal Bremerton, WA, intertidal
found eating a Leukoma staminea

Birch Bay State Park, WA, intertidal, egg collar Freshwater Bay, WA, subtidal

Neverita lewisii (Gould, 1847)
Lewis's Moonsnail *
intertidal to 180m northern Mexico to southern Alaska; Japan size to 14cm
This is commonly found intertidally. The shell's large size cannot be mistaken for another. It has a brown, horny operculum. When the animal extends out of the shell, it is much larger than the shell. This predatory animal hunts clams, which it then drills into and eats. By extruding all the excess water, the animal can then retract completely back into the shell. The fully extended animal in the lower right photo is over a foot long. The distinctive, large egg collars are often seen on the beach as well.
(synonyms - Euspira lewisii, Polinices lewisii, Lunatia lewisii, Natica lewisii, Polinices algidus)

Family Velutinidae & Naticidae