''Mangelia theskeloides'' 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 Mangeliidae.The Annals and Magazine of Natural History, vol. 4 , s. 7; London, 1899

Description

The length of the shell attains 8 mm, its diameter 4 mm. (Original description) The fusiform, somewhat solid shell becomes attenuate towards the apex. It contains seven

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 whorls of 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 ...

are imperfect in all the examples examined. They are tinged with blackish brown. The subsequent whorls are turreted, tumid and brightly ochraceous. They are ornamented with strong longitudinal ribs, which number eleven 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 ...

. These are crossed by spiral close striae, which are not shown on elder worn specimens. The most conspicuous feature is a series of darker blackish-brown zones,.one just above the suture of each whorl and another in the centre of the lowest. These zones are interrupted and only appear between the ribs, the remainder of the surface being painted with light brown scattered dots and flames, a series of light spiral maculations just below the sutures being specially prominent. The aperture is narrow, oblong, the dark zone shows transversely across the interior. The outer lip is incrassate, sinus very obscure. The columella is straight and stained with brown at the base.

Description

Distribution

References

External links