seashell
hard, protective outer layer created by an animal
Periostracum
outermost layer of the shell in many shelled animals
mollusc shell
exoskeleton of an animal in the phylum Mollusca
bivalve shell
seashell
test
hard shell of some spherical marine animals, notably sea urchins and microorganisms such as testate foraminiferans, radiolarians, and testate amoebae
dentalium shell
Material used in Native American jewelry