''Raphitoma enginaeformis'' 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

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 ...

.G. & H. Nevill, Descriptions of New Marine Mollusca from the Indian Ocean; The journal of the Asiatic Society of Bengal. vol. 44 p. 2, 1875
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Description

The shell reaches a length of 5½ mm and a diameter of 2½ mm. (Original description) The shell is narrowly elongate, convex, in shape resembling several species of the genus Engina Gray, 1839. The shell is peculiarly attenuated and contracted towards the base, the spire pointed. The color of the shell is white, banded with a single somewhat irregular yellow band, repeated a little below the middle 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 ...

. Some of the granules on this band are yellow, whilst others are white. The shell 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, distantly reticulated with thick, obtuse, longitudinal and transverse keels. The interstices, under a lens, are minutely and closely longitudinally striated. The sculpture is very distinct and clearly marked on the last two whorls, but much confused and difficult to trace on the upper ones. Pearl-like granules are formed where the ridges cross one another, in the present shell however they are more regular in size and more rounded. There are three rows of these granules on each whorl, besides an additional smaller one and some indistinct transverse ridges close to the suture. There are ten longitudinal keels on the body whorl. The sinus is deep, but rather contracted, bent down rather abruptly. The aperture is very straight and narrow, suddenly widening a little close to 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 ...

. There are seven rather large regular granules at the inner margin of the outer lip.

Distribution

This marine species occurs in the Indian Ocean off

Sri Lanka Sri Lanka (, ; si, ශ්‍රී ලංකා, Śrī Laṅkā, translit-std=ISO (); ta, இலங்கை, Ilaṅkai, translit-std=ISO ()), formerly known as Ceylon and officially the Democratic Socialist Republic of Sri Lanka, is an ...

References

External links

Worldwide Mollusc Species Data Base: ''Raphitoma enginaeformis''
{{DEFAULTSORT:Raphitoma Enginaeformis enginaeformis Gastropods described in 1875