Question

What is the function of statocyst in snails?

Answer 1

Mollusca are the second largest phylum of the animal kingdom. This phylum includes the soft-bodied animals. Their body is covered by a calcareous shell and is unsegmented with a distinct head, visceral hump and muscular foot. Head bears mouth, tentacles, eyes, etc. in some mollusks.

Complete answer:
Molluscs are found in all habitats i.e., they are terrestrial as well as aquatic. Molluscs have a visceral hump containing the digestive tract and some visceral organs. Foot may be a large muscular part of the body which is chiefly a locomotors organ.
A soft and spongy layer of skin forms a thin and delicate covering over the visceral hump or pallial complex and is called mantle. This mantle is a characteristic feature of molluscs. It provides protection to the head and secretes a calcareous shell over the body that acts like an exoskeleton.
The anterior head region may have sensory tentacles which are sensitive to the touch. Along With tentacles, other sense organs like eyes for light detection, statocysts for balance and receptors for smell and taste are also present in their body which makes these animals aware of their surroundings to urge food, shelter and protection. Osphradium may be a sensory structure which tests the chemical nature of water.
Gastropoda is the largest class of molluscs comprising limpets, slugs, snails, etc. A characteristic feature that distinguishes all gastropods from other molluscs is torsion. Their shell is made up of one piece enclosing the visceral mass. The buccal cavity has an odontophore with a radula bearing chitinous teeth. There is a veliger larva during the event. The early embryo is symmetrical with anterior mouth and posterior anus but during development the body twists bringing the anus near the mouth showing torsion so that the body becomes asymmetrical. Thus, in the adult forms the mouth and the anus are anterior.
Some examples of gastropods include Pila , Aplysia , Doris , Patella , Limax , etc.

Note:
Kokichi Mikimoto of Japan is known to be the father of the pearl industry. He discovered a method to induce foreign particles between the mantle and the shell of the pearl oyster. This stimulated the pearl formation in oysters. This method of artificially inducing the foreign particle is used to make artificial pearls.