''Drillia investigatoris'' 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

Drilliidae The Drilliidae are a Taxonomy (biology), taxonomic family (biology), family of small predatory sea snails with high-spired shells. They are classified as marine (ocean), marine gastropod mollusks in the superfamily Conoidea. This family has no s ...

Description

The length of the shell attains 65 mm, its diameter 20 mm. The reddish-brown shell has a fusiform shape. It shows a pale band above the middle of the

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 ...

. The longitudinal ribs are strongly rounded. They do not extend beyond 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 ...

. These ribs are crossed by many spiral lirae. The shell contains 12 whorls, two of which in 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 ...

. These two are smooth, white and globose. The others are slightly concave above the suture and then slightly obtuse. The aperture is narrow and measures almost half the length of the shell. The outer lip is sinuate close to the suture. The columella is straight and oblique.Smith, E.A. (1899) Natural history notes from H. M. Indian Marine Survey Steamer Investigator,Commander T. H. Heming, R. N.-Series III., no. 1. On Mollusca from the Bay of Bengal and the Arabian Sea. Annals and Magazine of Natural History, series 7, 4, 237–251
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Distribution

This species occurs in the demersal zone off the

Andaman Islands The Andaman Islands () are an archipelago in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a maritime boundary between th ...

References

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1–1295

External links

* {{DEFAULTSORT:Drillia Investigatoris investigatoris Gastropods described in 1899