Trichotropis cancellata Hinds, 1849

Common name(s):  Checkered hairy snail, Cancellate hairysnail, Hairy snail

Class Gastropoda
Order Mesogastropoda
Suborder Taenioglossa
Trichotropis cancellata
(Photo by: Dave Cowles, July 2007)
Description:   Members of Family Trichotropidae have a coiled, raised spire, much of the periostracum is in the form of hairs or bristles, and have no siphonal notch or canal (though the anterior end of the aperture is angled to form a spoutlike opening)(photo). Trichotropis cancellata has 6-7 whorls, an aperture less than half the height of the shell, and a diameter about 2/3 the shell height.  The shell has both small longitudinal and 4-5 pronounced spiral ridges.  The periostracum is light brown.   Length to about 4.2 cm.

How to Distinguish from Similar Species:   Several other Trichotropis species have an aperture at least half the height of the shell.  May look like a small Oregon triton Fusitriton oregonensis, but the aperture is more circular in Trichotropis.

Geographical Range:  Bering Sea to Oregon

Depth Range:  Extreme low intertidal to 200 m.  Mostly subtidal

Habitat:  Areas of strong currents and little mud.  Often under subtidal rocks, among tunicates and tubeworms.  May climb up the tubes of large tubeworms.

Biology/Natural History:  This species is a filter feeder.  It traps microscopic particles in mucus, which it then swallows.  Since its food comes from suspended particles it has no need to move around much.  It mounts a stone or other object out of the mud and remains there for a long time.  Deep-water individuals frequently have the tiny white parasitic snail Odostomia columbiana next to the aperture. Odostomia uses its eversible proboscis to suck body juices from TrichotropisTrichotropis also often has ascidians, hydroids, diatoms, sponges, barnacles, or other sessile animals growing on it.  This species is a protandric hermaphrodite.  For its first year it is a male, then becomes female but retains the penis (behind its right eye).  Females lay disk-shaped egg capsules at night, then die.

Cancellate means checkered.  The spiral and longitudinal ridges form a checkered pattern on the shell, but the pattern is often hard to see because of the thick hairy periostracum.



Dichotomous Keys:
  Flora and Fairbanks, 1966 (with incorrect illustration)
  Kozloff 1987, 1996

General References:
  Griffith, 1967
  Harbo, 1997

  Johnson and Snook, 1955
  Kozloff, 1993
  Morris, 1966

  O'Clair and O'Clair, 1998

  Rice, 1973
  Ricketts et al., 1985

  White, 1976

Scientific Articles:
Yonge, C.M., 1962.  On the biology of the mesogastropod Trichotropus cancellata Hinds, a benthic indicator species.  Biological Bulletin 122: 160-181 

Web sites:

General Notes and Observations:  Locations, abundances, unusual behaviors:

The species has a horny operculum.  The foot is pink.  The aperture is less than half the height of the shell and has no siphonal notch but the anterior end of the aperture (the right side in the photo above) is angled like a spout. 

Another view of  the snail pushing back its operculum and looking out the aperture.  Photo by Dave Cowles, August 2012

Authors and Editors of Page:
Dave Cowles (2007):  Created original page
CSS coding for page developed by Jonathan Cowles (2007)