CLASSIFICATION OF PLANORBIS (RAM'S HORN SNAILS)
KINGDOM :- ANIMALIA (Multicellular eukaryotic organisms)
PHYLUM :- MOLLUSCA (Unsegmented bilaterally symmetrical and provided with visceral mass, foot and mantle.)
CLASS :- GASTROPODA (Head bearing tentacles, eyes and radula; visceral hump and shell coiled due to torsion.)
SUB-CLASS :- EUTHYNEURA (Nerve loop not twisted in figure of 8.)
ORDER :- PULMONATA (Air-breathing forms.)
SUB-ORDER :- BASOMMATOPHORA (Eyes at the base of tentacles.)
FAMILY :- PLANORBIDAE (air-breathing freshwater snails)
GENUS :- Planorbis
It is commonly found in India and Europe.
HABIT AND HABITAT
Planorbis is another abundant and most common fresh-water, air-breathing gastropod, found in ponds and lakes in large numbers.
GENERAL CHARACTERSTICS OF PLANORBIS (RAM'S HORN SNAIL)
- Animal is enclosed in black, stout and spirally coiled shell.
- Shell is sinistral and discoidal having a depressed or flattened spire.
- Head protrudes through the shell opening. It contains filiform tentacles and a pair of eyes.
- Mantle lobe outside pulmonary cavity is transformed into a functional gill.
- Unlike most molluscs, the blood of ram’s horn snails contains iron-based hemoglobin instead of copper-based hemocyanin.
- Planorbids are able to breathe oxygen more efficiently than other molluscs.
- Planorbids do not have gills, but instead have a lung.
- The foot and head of planorbids are rather small, while their thread-like tentacles are relatively long.
- They carry their shell in a way that makes it appear to be dextral
The animal contains flattened spirally coiled spire and all above features, hence it is Planorbis.