Odostomia atossa
Encyclopedia
Odostomia atossa is a species
of sea snail
, a marine
gastropod mollusk in the family
Pyramidellidae
, the pyrams and their allies.
are small, deeply obliquely immersed in the first of the succeeding turns, above which only the tilted edge of the last volution projects. The five post-nuclear whorls are inflated, well rounded and feebly contracted at the sutures. They are very weakly shouldered at the summit, marked by fine, slightly retractive lines of growth, and by 7 incised spiral lines on the first, 10 on the
second, and 20 on the third. On the last whorl they are very feeble between the sutures, where they are replaced by four slender, spiral threads. The periphery of the body whorl
is inflated. The base of the shell is inflated, well rounded and marked by numerous, closely spaced, fine spiral striations. The aperture
is large, ovate. The postenor angle is acute. The outer lip
is thin. The columella is moderately strong, strongly curved, decidedly reflected, partly reenforced by the base and provided with a fold at its insertion.
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 large, ovate shell is bluish-white. The nuclear whorlsWhorl (mollusc)
A whorl is a single, complete 360° revolution or turn in the spiral growth of a mollusc shell. A spiral configuration of the shell is found in of numerous gastropods, but it is also found in shelled cephalopods including Nautilus, Spirula and the large extinct subclass of cephalopods known as the...
are small, deeply obliquely immersed in the first of the succeeding turns, above which only the tilted edge of the last volution projects. The five post-nuclear whorls are inflated, well rounded and feebly contracted at the sutures. They are very weakly shouldered at the summit, marked by fine, slightly retractive lines of growth, and by 7 incised spiral lines on the first, 10 on the
second, and 20 on the third. On the last whorl they are very feeble between the sutures, where they are replaced by four slender, spiral threads. The periphery of the body whorl
Body 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...
is inflated. The base of the shell is inflated, well rounded and marked by numerous, closely spaced, fine spiral striations. The 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 large, ovate. The postenor 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. The columella is moderately strong, strongly curved, decidedly reflected, partly reenforced by the base and provided with a fold at its insertion.