Mollusca is the second largest phylum of animals, the first being Arthropoda. This phylum is generally characterized by a shell, although a few groups would go on to lose their shells like in Slugs & some Cephalopods.
Mollusca is the second largest phylum of animals, the first being Arthropoda. This phylum is generally characterized by a shell, although a few groups would go on to lose their shells like in Slugs & some Cephalopods.