''Agladrillia benjamini'' 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 species attains 15.3 mm, its diameter 5.7 mm. (Original description) The elongate-conic shell is flesh colored. 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 calle ...

contains more than 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 flo ...

. The whorls of the teleoconch are strongly rounded. The sinus falls at the summit where the whorls are somewhat contracted. The surface of the whorls of the teleoconch are marked with strong, rounded, protracted axial ribs, which begin practically anterior to the sinus and extend strongly to the periphery. They are scarcely defined anterior to this on the body whorl. Of these ribs 10 occur upon the first to fourth, 12 upon the fifth to seventh, and 14 upon the penultimate whorl. The axial ribs are about as wide as the spaces that separate them. In addition to these axial ribs the whorls are marked by numerous slender spiral threads, of which about 5 occur in the area of the sinus on the last three turns. These are finer than those that cover the rest of the turn between the sutures. Of the latter, three occur on the first to third, four on the fourth, seven on the fifth and sixth, eleven on the next, and thirteen on the last turn. The spaces between the spiral threads about equal the spiral threads in strength. The surface between the spiral threads is covered with fine granulations on 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 ...

. The last whorl anterior to the periphery is marked by 27 spiral cords, which are about equal and equally spaced, being only a trifle stronger on 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 ...

. The sutures are well constricted. 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 ...

shows a strong deep sinus at its posterior angle, which renders 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 ...

, anterior to this, decidedly claw-like. The outer lip is strongly re-enforced within by a callus that bears about 15 denticulations on the inner surface. The columella and the parietal wall are glazed with a thin callus.P. Bartsch (1915), Report on the Turton collection of South African marine mollusks, with additional notes on other South African shells contained in the United States National Museum; Bulletin of the United States National Museum v. 91 (1915)
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Distribution

This marine species occurs off South Africa.

References

External links

P. Bartsch (1915), Report on the Turton collection of South African marine mollusks, with additional notes on other South African shells contained in the United States National Museum; Bulletin of the United States National Museum v. 91 (1915)
{{DEFAULTSORT:Agladrillia Benjamini benjamini Gastropods described in 1915