what is mollusca
By Laura Klappenbach. Mollusks (Mollusca) are a group of invertebrates that includes squid, octopuses, cuttlefish, nudibranchs, snails, slugs, limpets, sea hares, mussels, clams, oysters, scallops, as well as many less well-known animals.Scientists estimate that there are more than 100,000 species of mollusks alive today.This makes them the second largest phylum of animals, having fewer species than only the arthropods. Mollusks have soft bodies that consist of three basic parts: a foot, a visceral mass and a mantle.his hypothetical mollusk has a mantle, shell, foot and visceral mass. The mantle is a layer of tissue that covers the visceral mass and in many mollusks it contains glands which secrete a hard shell. The foot is muscular structure located on the underside of the body.