Gastropods

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

Cerithiopsidae

Oak Bay, WA, intertidal

Cerithiopsis sp. 1
This species gets to at least 4mm. The spiral and axial grooves form beading. The beading is somewhat flattened, especially in the later whorls.

Batillaria attramentaria (G.B. Sowerby I, 1855)
Mudflat Snail *
intertidal central California to central BC; Japan size to 50mm
This is commonly found and can be extremely abundant in places. It was
introduced from Japan with oyster seed. The shell has spiral ribbing and may be uniform in color, usually gray-brown, or striped with white. The interior of the aperture is dark. As the name suggests, it prefers mud or muddy sand.

Cerithiopsis sp. 3
This species is similar to #2, except that the sutures between the whorls seem less impressed and the body whorl more rounded.

Bittium vancouverense
Dall & Bartsch, 1910
intertidal to subtidal size to at least 10mm
southern BC to central Alaska
This is infrequently found. The shell is dark with spiral ridges and pronounced beading from axial grooves.

Neostylidium eschrichtii (Middendorff, 1849)
Threaded Bittium *
intertidal to 55m northern Mexico to southern Alaska size to 20mm
This is commonly found intertidally. It is the largest of the Bittiums in our area. They are found under rocks and are often inhabited by hermit crabs. The shell is gray to brown. It has flattened spiral cords and no axial grooves.
(previous names - Stylidium eschrichtii, Bittium eschrichtii, Turritella eschrichtii)
This is a recent change from Stylidium to Neostylidium. See reference - Doweld, A. (2013)

The Cerithiopsis are a little understood group in the Pacific Northwest which need further study. We do not attempt to identify them to species level at this time. Our numbering system does not correlate to any other reference, but is simply our own way to keep track of the types we have found. We are not sure exactly how many valid species exist in our area.

Tofino, BC Crane Island, WA Anacortes, WA, intertidal

Lirobittium attenuatum (Carpenter, 1864)
Slender Bittium
intertidal to 70m northern Mexico to southern Alaska size to 15mm
This is somewhat common. The early whorls show faint beading from axial grooves. The grooves taper off and the later whorls are smooth. It is more slender and does not grow as long as N. eschrichtii with which it might be confused. The shell is light in color but may have brown markings.
(synonyms - Bittium attenuatum, Bittium boreale, Bittium esuciens, Bittium latifilosum, Bittium multifilosum)

Campbell River, BC
Cerithiopsis sp. 2
This species gets to at least 4mm.
It is also beaded only the beads are rounded and rather prominent.

Family Batillariidae, Cerithiidae & Cerithiopsidae