Only one genus occurs in Central and Northern Europe, and that is Viviparus.
Genus: VIVIPARUS Montford, 1810
There are four species in Central and Northern Europe, namely:
V. contectus (Millet, 1813)
V. viviparus (Linnaeus, 1758)
V. ater (Christofori & Jan, 1832)
V. acerosus (Bourguignat, 1862)
(V. mamillatus (Küster, 1852) occurs in former Yugoslavia and in Albania).
Of these, only V. contectus and V. viviparus occur in Britain. Except for Lymnaea stagnalis, they are our largest freshwater snails. The shells are conical and have 6 or 7 whorls, with 2 or 3 dull brown spiral bands on a greenish background. The operculum is horny and marked with concentric rings.
The right tentacle of the male is shorter, blunter and appears deformed when compared with the left, because, in this genus, it is modified at the tip to allow the penis to protrude. The eyes are borne on knobs at the base of the long tentacles.
As is indicated by the name of this genus, the eggs are retained in the oviduct of the female until the embryos are fully developed, and the young are released from the mother in the late spring. When newly hatched the shell is clothed in hairs and there are three spiral bands of spines on prominent ridges, but these are lost in the adult.
Viviparus viviparus
(Linnaeus, 1758)
Viviparus viviparus (Linnaeus, 1758)
Description: The apex is blunt by comparison with V. contectus and the shell is not glossy. It is yellow-green to green-brown in colour with three red-brown spiral bands. The whorls are rounded, but not shouldered and the umbilicus is scarcely apparent. The operculum is oval and rather thick.
Size: Height: 33 – 40 mm. Breadth: 22-28 mm.
Habitat: Inhabits rivers and canals throughout the "Canal Basin" of central England and Wales.
Viviparus contectus
(Millet, 1813)
Viviparus contectus (Millet, 1813)
Description: The apex is sharply pointed (test with finger-tip!) Shell glossy; green-brown, with three red-brown spiral bands. The whorls are rather tumid and high shouldered, with a deep suture and a rather large and conspicuous umbilicus. The operculum is rounded,thin and reddish brown in colour.
Size: Height: 32 – 35 mm. Breadth: 22 – 30 mm.
Habitat: Inhabits rivers and canals throughout the "Canal Basin" of central England and Wales.