''Cymatosyrinx arbela'' 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

Drilliidae The Drilliidae are a Taxonomy (biology), taxonomic family (biology), family of small predatory sea snails with high-spired shells. They are classified as marine (ocean), marine gastropod mollusks in the superfamily Conoidea. This family has no s ...

Description

The length of the shell attains 13.7 mm, its diameter 5 mm. (Original description) The small, glistening shell is acute. Its color is brownish, with the projecting sculpture paler. 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 ...

is dark brown, glassy, rather irregularly coiled and consists of one smooth

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 ...

. It is followed by a peripherally keeled turn and about eight subsequent whorls. The suture is distinct, appressed, with a nodulose band in front of it where the ends of the ribs are cut off by a very narrow fasciolar constriction. The spiral sculpture consists of a few incised lines cutting only the interspaces between the ribs, on the spire. 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 ...

there are six or seven of these lines, with much wider interspaces, followed by three strong cords close-set on 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 ...

. The axial sculpture consists of (on the body whorl about 13) protractively oblique whitish narrow ribs extending from the fasciole to the cords of the siphonal canal, with subequal interspaces and not continuous up the spire. The silky incremental lines are evident. The aperture is narrow. The

anal sulcus The anal sulcus, also called the anal sinus or anal canal, in Gastropods is a notch, a shelly tube at the top of the aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and fo ...

is deep and rounded, with a strong subsutural callus. The outer lip is sharp-edged, with a feeble

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 ...

and a brown spot behind it. The inner lip and the columella shows a thick coat of white enamel, the throat not lirate. The siphonal canal is constricted, very short, deep, and slightly recurved.Dall (1919) Descriptions of new species of Mollusca from the North Pacific Ocean; Proceedings of the U.S. National Museum, vol. 56 (1920)
(described as ''Elaeocyma arbela'')

Distribution

This species occurs in the demersal zone of tropical

Eastern Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the continen ...

; the holotype was found off Baja California, Mexico

References

* Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682: 1–1295.

External links

* {{DEFAULTSORT:Cymatosyrinx Arbela arbela Gastropods described in 1919