Another genus with only one species in it is Afropomus,the sole species being Afropomus balanoidea(Gould,1850).The shell is about 20 mm,globose and heavy. The color is chestnut brown with darkbrown spiral bands. The species lives in western Africa in small waters.
Yet another genus with only one recognized species is Marisa.The species is Marisa cornuarietis(Linnaeus,1758),although sometimes another species is described:Marisa planogyra. The shell of Marisa is discoidal,like in the genus Planorbis.Sometimes Marisa is being sold as a giant Ramshorn snail.It can be about 35-50 mm in diameter, female shells being larger than males.The color is yellowish brown with reddish brown to dark-brown bands,although in the aquariumtrade yellow snails without bands are sold. This species is a voracious eater and not very suitable for aquaria with planting. In nature they eat whatever they find:live or dead plants,carrion and eggs of other snails. The snails live in shallow waters with rich vegetation in South-America(Venezuela, Brazil,Columbia,etc),but is wide spread in other parts of the world as well due to import. The orange eggs are laid in the ...