Hima mendica (Gould, 1850)

Common name(s): Lean western nassa, western lean dogwhelk, lean basketsnail, mud nassa, lean nassa

Synonyms: Nassarius mendicus,  Alectrion mendicus, Alectrion mendica, Nassarius cooperi, Nassarius indisputabilus Hima mendica
Class Gastropoda
Order Neogastropoda
Suborder Rachiglossa
Hima mendica, shell length 12 mm, found on mud flats along the eastern side of Padilla Bay. Note the yellowish foot and siphon, the round, horny operculum embedded in the foot, and the white tentacles with black eyespots.
(Photo by:  Dave Cowles, June 2022)

Description:  As with all members of family Nassariidae (Dogwhelks or nassa mud snails), the coiled shell has a well-developed spire and a siphonal notch or canal but no anal notch (though this species has a narrow posterior notch near where the anal notch would be found).  The outer shell is not highly polished and is usually sculptured.  The widest part of the aperture is less than half the diameter of the shell.  Has a horny operculum.  The lowermost portion of the body whorl, including the siphonal canal, is set off from the rest of the shell by a deep groove and upturned for most species in the family (see photos above and below). Both axial ribs and spiral ridges are well developed on Hima  mendica shells, creating a beaded appearance where they overlap.  The axial ribs are larger than the spiral ridges. These beads are not evenly spaced. The outside of the shell is grayish-brown, often with one or more darker brown spiral bands (see above), and the inside of the shell is white without an orange callus. The 12 axial ribs are larger than the spiral ridges and extend all the way to the groove at the base of the body whorl. Shell length to about 2.2 cm and more slender than most other family members such as N. fossatus. Has about 8 whorls. Animal body is yellow or white, with a very long, extended siphon and pinpoint black eyes on long tentacles. The foot and siphon of at least this individual have a yellow or orange tinge.

How to Distinguish from Similar Species:Illyanassa obsoleta does not have the deep groove at the anterior end of the body whorl. Several Nassarius species have more than 20 axial ribs which are about the same size as the spiral ridges.

Geographical Range:  Kodiak Island, Alaska to Isla Ascuncion, Baja California

Depth Range:  Intertidal to 75m

Habitat:  Sand, mud, rocks.

Biology/Natural History:  These roving scavenger snails have a very long siphon. Hermit crabs often inhabit their shells after the snail dies. On muddy bottoms it pushes its way through the sediment with its long siphon extended upwards into the water.



 

References:

Dichotomous Keys:
  Carlton, 2007
  Kozloff, 1987, 1996 (As Nassarius mendicus)

General References:
  Abbott, 1986
  Harbo, 1997, 2011 (As Nassarius mendicus)
  Johnson and Snook, 1955 (As Alectrion mendica)
  Kozloff, 1993 (as Nassarius mendicus)
  Lamb and Hanby, 2005 (As Nassarius mendicus)
  Morris, 1966
  Morris et al., 1980

Scientific Articles:
 

Web sites:


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

Incurrent siphon
In this photo the indificual crawls rapidly along the side of the petri dish with its siphon extended, searching for food. Photo by Dave Cowles, June 2022.


Authors and Editors of Page:
Dave Cowles (2022):  Created original page
CSS coding for page developed by Jonathan Cowles

Salish Sea Invertebrates web site provided courtesy of Walla Walla University