Characteristics
- Organisms in this phylum have three main regions: the mantle, head-foot, and visceral mass.
- These organisms also posses a mantle. The mantle is able to secrete a calcareous shell, which provides protection.
- Molluscs have a mantle cavity. This cavity serves in exchanging gases, excretion, getting rid of wastes, and releases reproductive products.
- These organisms are bilaterally symmetrical.
- During reproduction and development these organisms have trochophore larvae, spiral cleavage, and schizocoelous coelom formation.
- Molluscs have a coelom that only surrounds the nephridia, heart, and gonads.
- These organisms posses an open circulatory system. However, class cephalopoda does not have an open circulatory system.
- Molluscs have a radula, which serves in scraping food.