Why are snails called snails?

I only know the story of snail girl. There is no mention of the origin of snail's name.

Once upon a time, there was a lonely young farmer who made a living by farming for the landlord. He works at sunrise and returns at sunset every day, working hard. One day, he found a very big snail in the field. He was surprised and happy. He took it home, put it in a water tank and raised it carefully with water.

One day, the farmer went to work in the field as usual in the morning, but when he came home the next day, he found delicious rice on the stove, delicious fish and vegetables in the cupboard and boiling hot water in the teapot. Two days, three days ... every day, the farmer decided to make things clear. The next day, the rooster crowed everywhere. As usual, he went down to work with a hoe on his back. He hurried home at dawn to see who was kind. He saw the chimney on the roof of his house smoking in the distance, so he went forward to see who was cooking with his own eyes. But when he crept close to the door and looked in, there was no movement at home. When he walked in, he saw that the food on the table was delicious, the fire in the kitchen was still burning and the water in the pot was boiling. The enthusiastic chef disappeared before he could scoop it up.

One day has passed. The farmer got up early again, the rooster crowed and went home before dawn. Before the kitchen smoke rose, Xie Duan quietly approached the fence, hid in the dark, and watched everything in his room with rapt attention. After a while, he finally saw a beautiful young girl slowly coming out of the water tank, and her clothes were not slightly wet because of the water. The girl moved to the stove and began to cook and cook.

Seeing the truth, the young man ran into the door and walked to the water tank. When he saw it, the snail he picked up was just an empty shell. He looked at the empty shell again and again in surprise, then went to the fire and said to the young girl who was cooking, "Girl, where are you from?" Why did you help me cook? "The girl didn't expect him to appear at this time. After listening to his questioning about his life, she was surprised and didn't know what to do. The girl wanted to go back to the water tank, but she was blocked. The young farmer kept asking, but the young girl had no choice but to tell him the truth. She is a snail girl.

Young people like snail girl very much, and later they got married.

Leech essence likes snail girl very much. Seeing that the snail girl and the farmer were so good, she was jealous and decided to take the snail girl away. So she pretended to be a fortune teller and cheated the snail shell from her blind mother-in-law. With the snail shell, the snail girl was collected by leeches and could not get out of his hole. Farmers and their partners went to the hole of leech essence to save snail girl, but they were defeated by leech essence. Later, they thought of a way to sprinkle salt on leech essence. Leech essence is most afraid of salt and finally dies in pain.

Snail girl and farmer live a happy life. A year later, she gave birth to a fat boy. In a blink of an eye, at the age of 5 or 6, she was playing with water by the river, and was later called the snail's child by her companion's children. "Fold, fold, fold, which female snail shell, ding, ding, which female snail essence." His son listened to others and hid his mother's shell, and the snail girl would never turn back into a snail.