''Monodonta vermiculata'',

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

the toothed topshell, 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 Trochidae, the top snails.

Description

The height of the shell attains , its diameter . The imperforate, solid, thick shell is subglobose. The short spire is conoid. The shell contains 4 to 5

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 penultimate and last whorl are quite convex, the last descending, more or less concave just below the linear suture. The young shells are obsoletely spirally lirate, their sculpture disappearing with age. The coloration consists of numerous narrow red or orange zones alternating with bands of light green articulated with black. The oblique aperture is round-ovate. The outer lip is finely plicate within. The basal lip is thickened and plicate. The short columella terminates in an acute tooth. The middle of the columellar area contains a longitudinal semilunar groove, frequently irregularly curved. The basal notch or canal is oblique, squarish, wider than deep, and not denticulate in the middle. There is great variation in color in this species. In some specimens red predominates, in others green. And often the general effect is an olive shade. There is usually a subsutural series of light and dark dashes. The numerous narrow red spiral lines are characteristic.Tryon (1889), Manual of Conchology XI, Academy of Natural Sciences, Philadelphia
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Distribution

This species occurs in the Red Sea, off Socotra and Muscat

References

* Donald K.M., Kennedy M. & Spencer H.G. (2005) ''The phylogeny and taxonomy of austral monodontine topshells (Mollusca: Gastropoda: Trochidae), inferred from DNA sequences''. Molecular Phylogenetics and Evolution 37: 474–483 {{DEFAULTSORT:Monodonta Vermiculata vermiculata Gastropods described in 1874