Rammshorn snails.
The shells are discshaped and brownish or greyish.The animals have long thin tentacles.
The blood contains hemoglobin which gives them a reddish color.
Rammshorn snails have to get to the watersurface to take in oxygen.But they can
stay longer under water than pondsnails.
Planorbarius(Planorbus) corneus(Linnaeus,1758)
The shell is yellow-grey or yellow-green,dark brown-red or brown.
It is discoid and has 5-6 whorls.It can grow up to 35mm in height and 15mm in width
but is usually smaller.The body of the animal is grey-brown with reddish tentacles.
When the temperature rises above 12 degrees celsius eggs are laid.The clusters
can contain about 100 eggs.They hatch after 15-18 days.The snails can
get 2-4 years old.In aquariums they live longer.
They feed on algae,waterplants and carrion in stagnant or slow streaming water
with a rich vegetation.
In Europe and West-Asia.
Planorbis carinatus(Müller,1774) Shell width 18 mm x height 3,5 mm with up to 5 whorls. The animal is dark greyish-brown,with reddish tentacles. Reproduction starts from May to July,the eggs hatch in 14-17 days. The snails live for about 2 years.They feed on dying or dead waterplants and algae. In Europe in calm,clear water with a rich vegetation.
Planorbis planorbis(Linnaeus,1758) Shell with up to 6 whorls,width up to 20 mm x height 4 mm. The animal is dark greyish-brown. The eggs are laid 6 days after mating,they hatch in 11-14 days in a temperature of 20 degrees celsius.The snails can reach an age of 3-4 years,although most of them die at a younger age(25-28 months).Young snails are born in February and produce new snails in July.They grow,hibernate and die in the next season. They feed on algae,dying and living plants. In calm water with a rich vegetation and a muddy bottom. In Europe,North-Africa and West-Asia.
Planorbella campanula(Say,1821)
In North-America.
Planorbella scalaris(Jay,1839)
In Florida.
Planorbella tenuis(Dunker,1850)
In southern North-America and Mexico.
Planorbella trivolvis(Say,1817)
In North-America and Canada.
Anisus leucostoma(Millet,1813) The shell is 9mm wide and 1,5mm high,with up to 6,5 whorls. The animal is reddish brown with lighter colored tentacles. Eggs are laid from the beginning of April till the beginning of August.They hatch between 28 till 6 days depending on the temperature. The snails live for 12-14 months and feed rotting plant parts. In Europe,Iceland,North-Africa and Siberia in sweet or brackish water and marshes.
Anisus spirorbis(Linnaeus,1758) Shell is 8mm wide and 2mm high,with up to 5 whorls. The body of the animal is grey-brownish black with lighter colored tentacles. They feed on plants in calm sweet or brackish water. In Europe to Siberia.
Anisus vortex(Linnaeus,1758) The shell is 18-10 mm wide and 1-1.5 mm high,with up to 7 whorls. Eggs are laid in early spring and hatch after 10 till 12 days. The snail feeds on algae and rotting leaves.In calm or streaming water with a rich vegetation. In Europe and West-Asia.
Anisus vorticulus(Troschel,1834) The shell is 6mm wide and 0.8mm high,with up to 5,5 whorls. The animals live for one year in clear water with a rich vegetation. In Central- and Eastern-Europe.
Bathyomphalus contortus(Linnaeus,1758) Shell is 7mm wide and 2mm high,up to 8 whorls. The animal is blackish with long tentacles. The start laying eggs in March.They feed on bacteria in calm or streaming water with a rich vegetation. In Europe to Siberia.
Gyraulus crista(Linnaeus,1758) Shell is 4mm wide and 1mm high,up to 3 whorls. The body is grey-yellowish with dark spots. The eggs start to hatch in April,this continues till July.They live in stagnant sweet or brackish water with a rich vegetation. In Europe.
Gyraulus albus(Müller,1774) Shell is 9mm wide and 2mm high,but usually smaller.The animal is reddish-brown with colorless tentacles.Reproduction starts from the end of June till October. The eggs hatch after 19-23 days.Snails which are born in June reproduce in September. They live from 12-17 months in stationary or streaming sweet water. In Europe,Eurasia and North-America.
Gyraulus parvus(Say) Shell flat and disc-shaped,reddish or greyish brown in coloring. Height is 1-1.5 mm and 4-5 mm in diameter. In ponds and slowly flowing brooks on the underside of plants,wood and leaves. In North-America,east of the Rocky-Mountains and south to South-Carolina.
Helisoma trivolvis(Say,1816) The snails have a discoid,sinistral shell with 5 whorls. It is 10-15 mm heigh and 18-30 mm wide,and has a yellowish to brown coloring. This species lives in North-America in lakes or stagnant water.There are several sub-species.
Helisoma anceps(Menke,1830)
Shell 11-15 mm in diameter.
In North-America.
Hippeutis complanatus(Linnaeus,1758) Shell with up to 4 whorls and a keel,width 5,1 mm x height 1,5 mm. The animal is grey-yellow with dark tentacles. In calm water with a rich vegetation. In Europe,North-Africa and West-Asia.