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Upper image: Lateral view showing the profile of the shell. Lower image: Umbilical view; this side is carried uppermost in the living snail. This species, like all planorbids, has a sinistral shell. The width of the shell is 15 – 20 mm. The keel on the periphery of the shell is near the edge closest to the spire side, which is carried ...
Morphology of typical spirally coiled shell. The shell of Zonitoides nitidus, a land snail, has dextral coiling. Upper image: Dorsal view, showing whorls and apex Central image: Lateral view showing the profile of the shell Lower image: Basal view showing umbilicus in the centre. Photo of the shell of Zonitoides nitidus with an
The anatomy of a common air-breathing land snail: much of this anatomy does not apply to gastropods in other clades or groups. Snails are distinguished by an anatomical process known as torsion, where the visceral mass of the animal rotates 180° to one side during development, such that the anus is situated more or less above the head. This ...
Haeckel (left), 1866 Sea snail shells, Kunstformen der Natur, 1904. Ernst Heinrich Philipp August Haeckel (February 16, 1834 – August 9, 1919), also written von Haeckel, was an eminent German biologist, naturalist, philosopher, physician, professor and artist who discovered, described and named thousands of new species, mapped a genealogical tree relating all life forms, and coined many ...
A snail is a shelled gastropod. The name is most often applied to land snails, terrestrial pulmonate gastropod molluscs. However, the common name snail is also used for most of the members of the molluscan class Gastropoda that have a coiled shell that is large enough for the animal to retract
Snails in the family Physidae have shells that are sinistral, which means that if the shell is held with the aperture facing the observer and the spire pointing up, then the aperture is on the left-hand side. The shells of Physella species have a long and large aperture, a pointed spire, and no operculum. The shells are thin and corneous and ...
The anus is located on the right side of the snail, above the genital opening. [5] In the excretory system, the nephridium is central, tending to the right side of the body, as a thin dark layer of glandular tissue. [5] The nephridium is anterior and ventral of the digestive gland, and is in contact with the dorsal side of the foregut. [5]
In gastropods, the body whorl, or last whorl, [1] is the most recently formed and largest whorl (or revolution) of a spiral or helical shell, terminating in the aperture.It is called the "body whorl" because most of the body of the soft parts of the animal fits into this whorl.