Odostomia acrybia
Encyclopedia
Odostomia acrybia is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
are well rounded, the latter marked by nine slender spiral cords, the spaces between which are crossed by fine axial threads. The oval aperture
is slightly effuse anteriorly The posterior angle is acute. The outer lip
is thin, showing the external sculpture within. The columella is twisted, decidedly reflected anteriorly and provided with a strong fold at its insertion. The parietal wall is covered with a thick callus.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of sea snail
Sea snail
Sea snail is a common name for those snails that normally live in saltwater, marine gastropod molluscs....
, a marine
Marine (ocean)
Marine is an umbrella term. As an adjective it is usually applicable to things relating to the sea or ocean, such as marine biology, marine ecology and marine geology...
gastropod mollusk in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Pyramidellidae
Pyramidellidae
Pyramidellidae, common name the pyram family, or pyramid shells, is a voluminous taxonomic family of mostly small and minute ectoparasitic sea snails, marine heterobranch gastropod molluscs or micromolluscs....
, the pyrams and their allies.
Description
The elongate-conic shell is milk-white. Its length is 3.2 mm. The seven post-nuclear whorls are very slightly rounded, somewhat contracted at the sutures, feebly shouldered at the summits. They are marked by strong, almost vertical axial ribs, of which 14 occur upon the second, 16 upon the third, 18 upon the fourth, 20 upon the fifth, and 22 upon the penultimate turn. The intercostal spaces are a little wider than the ribs, crossed by four slender spiral cords, the junction of which with the ribs renders them feebly nodulous. The sutures are strongly impressed but not channeled. The periphery and base of the body whorlBody whorl
Body whorl is part of the morphology of a coiled gastropod mollusk.- In gastropods :In gastropods, the body whorl, or last whorl, is the most recently-formed and largest whorl of a spiral or helical shell, terminating in the aperture...
are well rounded, the latter marked by nine slender spiral cords, the spaces between which are crossed by fine axial threads. The oval aperture
Aperture (mollusc)
The aperture is an opening in certain kinds of mollusc shells: it is the main opening of the shell, where part of the body of the animal emerges for locomotion, feeding, etc....
is slightly effuse anteriorly The posterior angle is acute. The outer lip
Lip (gastropod)
In the shell of a gastropod mollusk , the margin of the aperture is called the lip or the peristome. In other words, this is a term used to describe part of gastropod shell anatomy....
is thin, showing the external sculpture within. The columella is twisted, decidedly reflected anteriorly and provided with a strong fold at its insertion. The parietal wall is covered with a thick callus.