''Mangelia hecetae'' 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

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 ...

mollusk in the family Mangeliidae.W.H. Dall & P. Bartsch (1910), New Species of Shells; Memoir 14-N, Canada, Department of Mines, Geological Survey Branch, Ottawa, 1910

Description

The length of the shell attains 9 mm, its diameter 3.25 mm. (Original description) The small, thin shell has an acute-fusiform shape. It is externally of a greyish colour. It contains about seven

whorl 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 ...

s. The initial whorl is minute, and smooth; the second bulbous, and smooth. The next are finely reticulated by fine spiral threads, and somewhat protractive arcuate fine riblets. This sculpture gradually merges into that of the adult whorl. The latter comprise—on 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 ...

—eleven or twelve arcuate ribs, retractive from the suture, protractive from the shoulder of the whorl forward to the

siphonal canal The siphonal canal is an anatomical feature of the shells of certain groups of sea snails within the clade Neogastropoda. Some sea marine gastropods have a soft tubular anterior extension of the mantle called a siphon through which water is ...

. These ribs are narrow, low, rather rounded, and with interspaces of about twice their own width. The whorl slopes in a somewhat excavated manner from the suture to the shoulder, where there is a moderate angulation, sometimes forming a rather strong spiral cord. The rest of the surface is covered with very fine, close, even, spiral threading, a little coarser on the earlier whorls. The aperture is elongate and narrow. The

anal sinus The anal sinuses (rectal sinuses) are furrows in the anal canal, that separate the anal columns from one another. The anal sinuses end below in small valve-like folds, termed anal valves The anal valves are small valve-like folds at the lower ends ...

is wide and shallow. The columella is white, with anterior end attenuated. The interior of the aperture is white, with three brown spiral bands, wide and dark, on the inside of the outer lip, but not visible on the exterior of the shell. The outer lip is sharp except when a

varix A varix (pl. varices) is an abnormally dilated vessel with a tortuous course. Varices usually occur in the venous system, but may also occur in arterial or lymphatic vessels. Examples of varices include: * Varicose veins, large tortuous veins usua ...

is formed, when it is slightly reflected inward. There is no operculum. The siphonal canal is short and straight, . and rather wide.

Distribution

This marine species occurs off Barkley Sound, Vancouver Island, Canada.

References

External links

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1-1295.
* hecetae Gastropods described in 1910 {{mangelia-stub