''Paradrillia agalma'' 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

Horaiclavidae Horaiclavidae is a family of predatory sea snails, marine gastropod mollusks in the superfamily Conoidea. In 2011 this family was split off from the family Pseudomelatomidae (formerly the subfamily Crassispirinae McLean, 1971) by Bouchet P., Ka ...

Description

The length of the shell attains 18 mm, its diameter 6 mm. The small fusiform shell contains 11

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 superior ones are eroded), covered with a gray

epidermis The epidermis is the outermost of the three layers that comprise the skin, the inner layers being the dermis and hypodermis. The epidermis layer provides a barrier to infection from environmental pathogens and regulates the amount of water rele ...

. The lines of growth are rather strong and very flexuous, and on passing the delicate spiral lirae, except in the concavity above the angle of the whorls and at the base 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 ...

, are delicately nodulous. The last volution below the nodose periphery has about fifteen lirae, of which about six of the upper ones are nodulous, the rest, around the anterior contracted portion, being simple and thread-like. The tubercles on the angle are about eighteen in number, and the lirae above it three or four. The aperture is small. The outer lip is thin. The columella is almost upright and shows a small callus. 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 ...

is short. Smith, Edgar A. "XXV.—Natural history notes form RIMS ‘Investigator.’—Series III., No. 10. On Mollusca from the Bay of Bengal and the Arabian Sea." ; The Annals and magazine of natural history; zoology, botany; 7th ser. v. 18 (1906)
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Distribution

This marine species occurs 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

Tucker, J.K. 2004 ''Catalog of recent and fossil turrids (Mollusca: Gastropoda)''. Zootaxa 682:1-1295
{{DEFAULTSORT:Paradrillia Agalma agalma Gastropods described in 1906