Gastropods 

Family Rissoidae, Barleeidae,

Caecidae & Vermetidae 









Home > Northwest Shells & Marine Life > PNW Shells & Marine Life Photos > Gastropods >  Gastropods - Rissoidae, Barleeidae,
                                                                                                                                                                       Caecidae & Vermetidae









Rissoidae
 Alvania compacta Alvania compacta
                       Oak Bay, WA                                                  Oak Bay, WA, intertidal
Alvania compacta (Carpenter, 1864)
Compact Alvania
intertidal to 182m          northern Mexico to Alaska          size to 3mm
This is infrequently found due to its tiny size.  The shell is somewhat variable in size proportions and sculpture.  Usually the early whorls exhibit a crosshatch type sculpture.  This may become less prominent in the later whorls.  The protoconch is smooth.  The shell is brown in color.
(synonyms - Alvania filosa, Alvania pedroana)







< Previous     Next >








Caecidae
Caecum crebricinctum
Ucluelet, BC
Caecum crebricinctum
Carpenter, 1864

Giant Caecum
intertidal to subtidal          size to 6mm
northern Mexico to Alaska
This species is rarely found due to its small size.  
It grows in a tube shape with a plug on one end.  
As it grows, previously plugged portions fall off.
This shell has numerous fine axial rings.
Barleeiidae
Barleeia acuta Barleeia acuta Barleeia acuta
             Clayoquot Sound, BC                                    Haida Gwaii, BC                                       Monterey, CA                
Barleeia acuta (Carpenter, 1864)
Acute Barleysnail
intertidal to 73m          northern Mexico to southern Alaska          size to 5mm
This species has a smooth, brown shell which is shiny.  It may also exhibit a dark brown axial pattern.  It is large for a Barleeia.
(synonyms - Diala acuta, Barleeia marmorea, Barleeia dalli)





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

Onoba carpenteri
Ucluelet, BC
Onoba carpenteri (Weinkauff, 1885)
intertidal to subtidal          size to 2.6mm
northern Mexico to Southeast AK
This is infrequently found due to its tiny size.  It exhibits a fine crosshatch sculpture across the entire shell, even the protoconch. 
(synonyms - Alvania carpenteri, Alvania keenae, Alvania kyskaensis, Alvania montereyensis, Alvania sanjuanensis, Cingula eyerdami)

Onoba dinora
Victoria, BC
Onoba dinora (Bartsch, 1917)
intertidal to subtidal          size to 2mm
California to Southeast AK
This is infrequently found due to its tiny size.  It has deep suture lines and fine spiral lines.  There are no axial lines.  The protoconch is smooth.
(previous name - Alvania dinora











Home  About Us  Meetings&Events  Articles  Northwest Shells  Links  Contact Us  Site Map





















Vermetidae
Petaloconchus compactus Petaloconchus compactus
           off Lopez Island, WA, subtidal                                      Seppings Island, BC
Petaloconchus compactus (Carpenter, 1864)
Compact Worm Snail
intertidal to 50m          California to BC          size is irregular
This shell forms colonies and attaches to rocks or shells.  The growth
is irregular in shape.  The tubes are about 3mm in diameter.   They can be easily mistaken for some types of calcareous tubeworms.
(previous name - Bivonia compacta)

















This page last revised: 4-26-2015























































Caecum occindentale
Barkley Sound, BC
Caecum occidentale
(Bartsch, 1920)

Western Caecum
intertidal to subtidal          size to 3.8mm
northern Mexico to Alaska
This species is rarely found due to its small size.
  This shell usually has a white band behind the aperture.  It has a fairly smooth surface.
(synonyms - Fartulum occidentale, Fartulum hemphilli)