Calyptraea fastigiata Gould, 1846

Common name(s): Cup-and-saucer snail, Pacific chinese hat snail

Phylum Mollusca
 Class Gastropoda
  Subclass Prosobranchia
   Order Mesogastropoda
    Suborder Taenioglossa
     Family Calyptraeidae
Calyptraea fastigiata shell (dead) collected subtidally near Northwest Island
(Photo by: Dave Cowles, July 2005)
Description:  This limpetlike gastropod has a conical shell that is almost circular in outline.  Inside it has a spiral septum (shelf) with a twisted free edge that spirals about half a turn (photo).  Exterior of live individuals is white, interior pearly.  Diameter to 2.5 cm

How to Distinguish from Similar Species:  Slipper shells such as Crepidula adunca have a septum inside but the shells are more flattened, and the septum also is mostly flat rather than spiral.  The shells of chinese cap limpet Acmaea mitra has a similar shell shape but no septum inside.

Geographical Range:  Alaska to California

Depth Range:  Occasionally intertidal, mostly subtidal at 18 to 137 m

Habitat:  Attached to rocks, dead shells, or sometimes to crabs

Biology/Natural History:  As with other slipper shells, this species is a filter feeder with special gills.

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Dichotomous Keys:
  Kozloff 1987, 1996

General References:

  Harbo, 1997
  Morris, 1966

Scientific Articles:

Web sites:

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

Inside the shell there is a spiral septum, or shelf, which twists about 1/2 revolution

Authors and Editors of Page:
Dave Cowles (2005):  Created original page