Phylum Mollusca has a reduced coelomic cavity.
Mollusca is one of the most diverse groups of animals on the planet, with at least 50,000 living species. Phylum Mollusca is the second-largest phylum. They possess osphradia to test the chemical nature of water. Some characteristic features are
- They are bilaterally symmetrical.
- The body is soft and unsegmented.
- They have tissue-system grade of body organization
- Sense organs consist of eyes, statocysts, and receptors for touch, smell, and taste.
- The head comprises tentacles and compound eyes.
- They have a well-developed digestive system, the radula is the rasping organ for feeding.
- They have a pair of metanephridia that helps in excretion.