''Gymnobela vicella'' 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 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 e ...

in the

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

Raphitomidae Raphitomidae is a family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet P. & Rocroi J.-P. (Ed.) (2005). "Classification and nomenclator of gastropod families". ''Malacologia'' 47(1-2). . 39 ...

Description

The length of the (decollate) shell attains 8.5 mm, its diameter 4.5 mm. (Original description) The small, stout shell is subturrited. The nuclear

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 are eroded. 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 ...

is longer than 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 opt ...

, with about six whorls in addition to the nucleus. The color of the shell is white with a gray, olivaceous periostracum, the aspect much like a stumpy '' Bela'' Leach, 1847. The suture is distinct, not oppressed. The whorl in front of it is slightly constricted, sloping to a prominent keel at the shoulder. This slope is apparently coincident with the anal fasciole and is sculptured only by curved lines of growth and faint indications of axial ribs, which become more prominent in front of the shoulder. They become stronger on the earlier whorls and number about fifteen on the penultimate whorl. These ribs are feeble, with wider interspaces, rounded, and protective, becoming obsolete on the base and most 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 ...

. The spiral

sculpture Sculpture is the branch of the visual arts that operates in three dimensions. Sculpture is the three-dimensional art work which is physically presented in the dimensions of height, width and depth. It is one of the plastic arts. Durable sc ...

is strongest in the shoulder keel, which is a little nodulous where it crosses the ribs. In front of it are three to five spiral threads (on the spire) of which the second is strongest and faintly nodulous, the others feebler, more adjacent and simple These become more numerous by intercalation, the body whorl having about sixteen between the keel and the end of 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 lines of growth are rather strong and give the surface a rough appearance.;The

is short. The anal sulcus is shallow and feeble The outer lip is sharp, thin and simple. The columella is smooth, short and obliquely attenuated. The twisted siphonal canal is wide, short, funicular and slightly recurved.W.H. Dall (1908) Reports on the Mollusca and Brachiopoda, Bulletin of the Museum of Comparative Zoology at Harvard College. vol. 43
(described as ''Gemmula vicella'')

Description

Distribution

References

External links