''Splendrillia raricostata'' is a

species In biology, a species is the basic unit of Taxonomy (biology), classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of ...

of sea snail, a marine gastropod

mollusk 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 es ...

in the

family Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...

Drilliidae The Drilliidae are a taxonomic family of small predatory sea snails with high-spired shells. They are classified as marine gastropod mollusks in the superfamily Conoidea. This family has no subfamilies. It consists of about 30 genera and approxi ...

Description

The length of the shell attains 10 mm, its diameter 3⅓ mm. (Original description) The elongate, shining shell is horny brown. It contains 8

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 flo ...

s. Two whorls are apical transversely keeled and angled round the middle. The rest are concavely excavated above, convex below, coarsely obliquely plicated, and somewhat margined beneath the suture. The plicae terminate abruptly at the concavity, eight on a whorl, very oblique, gradually shorter on ascending the

spire A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are ...

, so that the upper rather acute ends fall about the middle of the whorls. The ribs on the body whorl are obsolete at the base, which is obliquely grooved. The

aperture In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture and focal length of an optical system determine the cone angle of a bundle of rays that come to a focus in the image plane. An ...

is very small, about one third as long as the whole shell. The sinus is deep, the inferior sinuation is shallow. The outer

lip The lips are the visible body part at the mouth of many animals, including humans. Lips are soft, movable, and serve as the opening for food intake and in the articulation of sound and speech. Human lips are a tactile sensory organ, and can be ...

is thin, curved and prominent, with a swollen

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 ...

some distance behind the margin. The

columella Lucius Junius Moderatus Columella (; Arabic: , 4 – ) was a prominent writer on agriculture in the Roman Empire. His ' in twelve volumes has been completely preserved and forms an important source on Roman agriculture, together with the ...

is scarcely oblique, but slightly sinuous covered with a callosity, tuberculated above at the suture. 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 very short and a little recurved. The color of the shell is horny brown. The

s are excavated above and somewhat margined at the suture. They show a few strong, oblique ribs, terminating above at the periphery. The body whorl is obliquely grooved at the base.G.W. Tryon (1884) Manual of Conchology, structural and systematic, with illustrations of the species, vol. VI; Philadelphia, Academy of Natural Sciences
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Distribution

This marine species occurs off Japan.

References

{{DEFAULTSORT:Splendrillia Raricostata raricostata Gastropods described in 1879