WordFlap 1 | Definition |
Phylum Mollusca | the coelomate animal phylum whose members possess a head-foot, visceal mass, mantle, and mantle cavity; most molluscs also possess a radula and a calcareous shell, nearly 100,000 species. |
Class Caudofoveata | wormlike molluscs with a cylindrical, shell-less body and scale-like, calcareous spicules; lack eyes, tentacles, statocysts, crystalline style, foot, and nephridia; deep-water, marine burrower; Chaetoderma; approximately 70 species. |
Class Aplacophora | shell, mantle, and foot lacking; wormlike; head poorly developed; burrowing luscs; marine; Neomenia; approximately 250 species. |
Class Polyplacophora | elongate, dorsoventrally flattened; head reduced in size; shell consisting of eight dorsal plates; marine, on rocky intertidal substrates; chiton; |
Class Monoplacophora | Molluscs with a single arched shell; foot broad and flat; certain structures serially repeated; marine; neopilina. |
Class Scaphopoda | Body enclosed in a tubular shell that is open at both ends; tentacles used for deposit feeding; no head. Marine; Dentalium; over 300 species. |
Class Bivalvia | body enclosed in a shell consisting of two valves, hinged dorsally7; no head or radula; wedge-shaped foot; marine and freshwater; Anodonta, Mytilus, Venus; approximately 30,000 species |
Class Gastropoda | shell, when present, usually coiled; body symmetry distorted by torsion; some monoecious species; marine, freshwater, terrestrial; Nerita, Orthaliculus, Helix; over 35,000 species. |
Class Cephalopoda | foot modified into a circle of tentacles and siphon; shell reduced or absent; head in line with the elongate visceral mass; marine, Octopus, Loligo, Sepia, Nautilus. |