page_title: Viviparus viviparus
section_title: Description
hierarchical_section_title: Viviparus viviparus / Description
caption_attribution_description: English: Drawing of the animal and shell of the common British river snail Viviparus viviparus Linneaus, 1758.
context_page_description: Viviparus viviparus is a species of large freshwater snail with a gill and an operculum, an aquatic gastropod mollusk in the family Viviparidae, the river snails.
context_section_description: The height of the shell is 25–35 mm. The width of the shell is 20–26 mm. Males are 2 mm smaller than females of the same age. The shell colour is dark greenish brown or greyish yellow with three reddish brown spiral bands. It is striated but not with a hammer pattern. The shell apex is blunt (more pointed in other Viviparus species). The shell has 5.5-6 weakly convex whorls. The last whorl is relatively large compared to that of other Viviparus species. The umbilicus is narrow. The animal can lock itself behind a round lid adorned with concentric striations (the operculum) , allowing it to protect itself-for several months if necessary - from dehydration. Once closed the operculum is flush with the opening of the shell.The operculum is attached to the dorsum and to the rear foot of this mollusc, the body of which is wide and T shaped and whose colour varies from spotted grey to greenish to orange.His mouth has a radula and a respiratory siphon opens on the right side of the head, feeding  gills located in front of the heart. This trap also allows the animal to filter the water.There are two short tentacles; the eyes are on the external side of each tentacle.
caption: Drawing of the animal and shell of Viviparus viviparus; a) head b) tentacles c) eyes d) foot e) operculum
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