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 Alvania compacta
                                                 a somewhat variable shell                                                                       photographed intertidally
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 shell is brown in color.







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Caecidae
Caecum crebricinctum
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.
Barleeidae
Barleeia acuta




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











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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)

















Vermetidae
Petaloconchus compactus
photographed subtidally
















This page last revised: 10-25-2012









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.














Caecum occindentale
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)