Gastropod includes Snails and slugs from saltwater, freshwater and land. Gastropod previously called Univalves. The anatomy, behaviour, feeding and reproductive adaptions of gastropods fluctuate considerably from one clade to another. 

Snail

Snail is the family of gastropod animals that tends to have an enclosing covering into which they can withdraw completely for safety. They fall into the category of the phylum Mollusca. Snails are mostly active in the monsoon season due to the moist temperature and are rarely seen in the winter season. They usually tend to destroy household fruits and vegetables. Snails are spread worldwide. They can be found in mountains, oceans, forests or deserts. Snails often plunge scapegoats on animals like lizards, snakes, birds and rats because they are tiny in the size. Snails have enclosed shells for hydration and safety purposes with this they are cold-blooded invertebrates. Animals who don’t have enclosing shells and look similar like Snail are named slugs. 

Anatomy of Snail Body

• A land snail’s body is attached to a coiled shell by a strong muscle. 
• During the resting period or protecting from a predator, the snail withdraws its body entirely into the shell. 
• A snail won’t able to leave its shell anyways easily. The shell always gets attached to them for life. 
• When a child snail hatches from an egg, its shell gives birth to only one whorl, i.e, one 360° orbit from the centre. 
• When a juvenile snail grows the shell size increase around the first whorl and it keeps on growing until the snail has attained its grown-up size. Though, snails’ number of whorls varies. 
• The waves present in the muscular contractions and expansion helps the snail to move ahead. 
• During the crawls, there is the secretion of mucus from the snail’s skin which lubricates the ground for movement. 
• The muscular foot and mucus help snail to move vertically or upside down smoothly. Even a snail can move over a sharp razor blade without getting a cut. 
• Snails breathe air almost as humans do. Snails inhale air from the lungs through the pneumostome. 
• In the snail lung, there is a tissue where gas exchange occurs, the oxygen is carried up by the blood and carbon dioxide is released.
• The mantle is a fold of skin that surrounds the snail’s body organs. Inside the shell, snails have body organs and systems. Snail body organs consist of the digestive gland, lung, heart and reproductive organs.
• Snails have various types of nerve cell endings which arise from bipolar and multipolar cells under the epidermis of their skin.
• Due to the rise of these bipolar and multipolar cells in the epidermis, they have a sense of touch and pain.
• When their body part is touched which is very soft, they can sense whether there is a danger that will retract them into their shell when necessary.

Conclusion 

Snails and shells are gastropods that occupy the taxonomic class of invertebrates under the phylum Mollusca and are commonly known as Gastropoda. These gastropods are from saltwater, freshwater and land as well and they are previously called Univalves. Their anatomy, behaviour, feeding and reproductive adaptations of gastropods fluctuate considerably from one clade to another. Snails have an enclosing covering which they can withdraw completely for safety and they are most common in the monsoon season due to moist temperature and are rarely seen in the winter season. They tend to destroy household fruits and vegetables.  They can be found in mountains, oceans, forests or deserts. Snails have enclosed shells for hydration and safety purposes with this they are cold-blooded invertebrates. Those animals who don’t have enclosing shells and look very similar to snails are named slugs.