The H. aspersas family tree is as follows ::
Species: Helix aspersa (brown garden snail)
Species: Helix aperta (green garden snail)
Species: Helix pomatia (escargot)
All animals are members of the Kingdom Animalia, also called Metazoa. This Kingdom does not contain the prokaryotes (Kingdom Monera, includes bacteria, blue-green algae) or the protists (Kingdom Protista, includes unicellular eukaryotic organisms). All members of the Animalia are multicellular, and all are heterotrophs (that is, they rely directly or indirectly on other organisms for their nourishment). Most ingest food and digest it in an internal cavity. 
The molluscs are a very successful group. If success is measured in terms of number of species and variety of habitats to which they have become adapted, then molluscs are one of the three most successful groups in the animal kingdom. Over 160,000 species have been described, of which around 128,000 are living and about 35,000 are recorded as fossil species.
The phylum also provides some of the most familiar animals, such as snails , clams , mussels , squids , and octopus. The earliest molluscs probably arose in the Precambrian , and nothing is known about what they were like.
Molluscs are found in nearly all habitats. In the sea they occur from the deepest ocean trenches to the intertidal* zone. They may be found in freshwater as well as on land where they occupy a wide range of habitats. Thus, during their evolution, they have become adapted to living in nearly all available habitats.
Gastropods are by far the largest group of molluscs. Their 40,000 species comprise over 80% of living molluscs. Gastropod feeding habits are extremely varied, although most species make use of a radula in some aspect of their feeding behavior. Some graze, some browse, some feed on plankton, some are scavengers or detritivores, some are active carnivores.
The Class Gastropoda includes the snails and slugs. Most gastropods have a single, usually spirally coiled shell into which the body can be withdrawn, but the shell is lost or reduced some important groups. Gastropods are characterized by "torsion," a process that results in the rotation of the visceral mass and mantle on the foot. The result is that the mantle cavity (including anus) lies in the anterior body, over the head and mouth, and the gut and nervous system are twisted. Torsion takes place during the veliger stage, usually very rapidly. Veligers are at first bilaterally symmetric, but torsion destroys this pattern and results in an asymmetric adult. Some species reverse torsion ("detorsion"), but evidence of having passed through a twisted phase can be seen in the anatomy of these forms. Many snails have an operculum, a horny plate that seals the opening when the snail's body is drawn into the shell.
An extensive division, or sub-class, of hermaphrodite gastropods, in which the mantle cavity is modified into an air-breathing organ, as in Helix, or land snails, Limax, or garden slugs, and many pond snails, as Limnea and Planorbis.
A division of Pulmonata in which the eyes are situated at the tips of the tentacles. It includes the common land snails and slugs.
Land snails including the common edible snail.
The most well known species are: Helix aspersa (Brown Garden Snail), Helix pomatia (Roman Snail, Burgundy Snail, and the Edible Snail).