In this article we will discuss about the structure of Apple Snail (Pila) with the help of a diagram.
1. It is commonly called “apple snail” and is found in fresh water ponds, pools and ditches in India and adjacent regions.
2. Shell is external and spirally coiled and is comprised of 6 whorls.
3. The axis around which coiling takes place is known as columella, the top whorl is known as apical whorl and the large and ultimate whorl is known as animal chamber.
4. The animal chamber is covered over by operculum.
5. Along the animal chamber runs a vertical groove the varix, which connects the penultimate whorl and inner lip of mouth.
6. The animal comprises a head, foot and a visceral mass.
7. Foot is muscular, flat and serves for creeping.
8. Visceral mass consists of main body organs and is spirally coiled.
9. Kidney and ctenidium (gill) unpaired.
10. A part of mantle is modified into pulmonary sac and serves for aerial respiration. The other mode of respiration being aquatic.
11. Sexes are separate and animal is herbivorous.