''Calliclava alcmene'' 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.

Description

The size of an adult shell varies between 13.5 mm and 19 mm. (Original description) The small shell is pinkish white and polished. It is acute, with a flat-topped

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 two polished, prominently peripherally keeled

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 and about eight subsequent whorls. The suture is appressed, with a retractively nodulous, thickened band in front of it, forming the posterior margin of the anal fasciole. The sculpture consists of (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 ...

22) somewhat sigmoid rounded ribs with subequal interspaces, reaching from the suture over the whorl to 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 ...

. They are constricted over the narrow anal fasciole and feebler on the anterior part of the body whorl. These ribs are cut into subnodulous segments by deep narrow sharp spiral grooves, with much wider interspaces, two or three on the spire, nine or ten between the fasciole and the siphonal canal on the body whorl. On the canal are five or six coarse close-set threads. The aperture of the holotype (probably not quite mature) is rather narrow. The anal sulcus is narrow, not deep. The outer lip is thin, sharp, prominently arcuate. The inner lip is erased. The columella is short and twisted. The short siphonal canal is hardly differentiated.Dall (1919) Descriptions of new species of Mollusca from the North Pacific Ocean; Proceedings of the U.S. National Museum, vol. 56 (1920)
(described as ''Clathrodrillia (Kylix) alcmene'')

Description

Distribution

References

External links