Mollusca vs. Echinodermata — What's the Difference?

Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda. The members are known as molluscs or mollusks ().

One of the grand divisions of the animal kingdom. By many writers it was formerly included in the Radiata.

Any of various skin diseases in which soft spherical tumors form on the face or the body.

Radially symmetrical marine invertebrates including e.g. starfish and sea urchins and sea cucumbers

One of the grand divisions of the animal kingdom, a phylum including the classes Cephalopoda, Gastropoda, Pteropoda, Scaphopoda, and Pelecyopoda (syn. Bivalvia, formerly called Lamellibranchiata, or Conchifera). These animals have an unsegmented bilateral body, with most of the organs and parts paired, but not repeated longitudinally. Most of them develop a mantle, which incloses either a branchial or a pulmonary cavity. They are generally more or less covered and protected by a calcareous shell, which may be univalve, bivalve, or multivalve.

Gastropods; bivalves; cephalopods; chitons