''Mitromorpha zilpha'' 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

Mitromorphidae Mitromorphidae is a monophyletic family of small to medium-sized sea snails, marine gastropod mollusks in the superfamily Conoidea.Bouchet, P. (2011). Mitromorphidae Casey, 1904. In: MolluscaBase (2018). Accessed through: World Register of Marin ...

Description

The length of the shell attains 6 mm, its diameter 3 mm. (Original description) The small, dull white shell is fusiform, with a large smooth white

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 ...

of 1½ whorls and 3½ subsequent

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 suture is distinct. The whorls are moderately rounded, sometimes with a shoulder in front of the suture. The axial sculpture consists of a variable number of rounded strong ribs (14 to 21 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 ...

) with interspaces wider or narrower in conformity with the number of ribs, extending over the whorls but obsolete near 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 spiral sculpture consists of fine threads, three or four on the penultimate and 10 or more on the body whorl, with wider interspaces, overrunning but not nodulating the ribs. The narrow aperture is semilunat. The outer lip is thin, smooth within, the body smooth. The columella is straight, with two rather strong oblique plaits. The siphonal canal is produced, its axis is minutely pervious.

Description

Distribution

References

External links