''Odostomia avellana'' is a species of

sea snail Sea snail is a common name for slow-moving marine gastropod molluscs, usually with visible external shells, such as whelk or abalone. They share the taxonomic class Gastropoda with slugs, which are distinguished from snails primarily by the ...

, a

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

gastropod The gastropods (), commonly known as snails and slugs, belong to a large taxonomic class of invertebrates within the phylum Mollusca called Gastropoda (). This class comprises snails and slugs from saltwater, from freshwater, and from land. T ...

mollusc Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...

in the family Pyramidellidae, the pyrams and their allies.Rosenberg, G. (2011). ''Odostomia avellana'' Carpenter, 1864. Accessed through: World Register of Marine Species at http://www.marinespecies.org/aphia.php?p=taxdetails&id=581103 on 2011-10-26

Description

The large, elongate-ovate shell is yellowish to milk white. Its length measures 8.3 mm. The

whorls A whorl ( or ) is an individual circle, oval, volution or equivalent in a whorled pattern, which consists of a spiral or multiple concentric objects (including circles, ovals and arcs). Whorls in nature File:Photograph and axial plane floral d ...

of the

protoconch A protoconch (meaning first or earliest or original shell) is an embryonic or larval shell which occurs in some classes of molluscs, e.g., the initial chamber of an ammonite or the larval shell of a gastropod. In older texts it is also called ...

are deeply vertically immersed. Only a part of the last volution is visible when viewed from above, their axis evidently being at a right angle to the axis of the later whorls. The five whorls of the teleoconch are increasing rapidly in size, early ones well rounded, later ones less so, their summits being closely appressed to the preceding whorl. The simple sutures are well impressed. The periphery and the base of the

body whorl The body whorl is part of the morphology of the shell in those gastropod mollusks that possess a coiled shell. The term is also sometimes used in a similar way to describe the shell of a cephalopod mollusk. In gastropods In gastropods, the b ...

are well rounded, the latter somewhat elongated. The aperture islarge, ovate, somewhat effuse anteriorly, milk-white within. The posterior angle is acute. The outer lip is thin at the edge, thick within. The short columella is curved and reinforced partly by the attenuated base, having a strong oblique fold at its insertion. The parietal wall is covered by a moderately strong callus. William Healy Dall and Paul Bartsch , "A Monograph of West American Pyramidellid Mollusks" , Smithsonian Institution, 1909
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Distribution

This species occurs in the Pacific Ocean off Vancouver Island.

References

External links

World Register of Marine Species
{{Taxonbar, from=Q3172290 avellana Gastropods described in 1864