Summary. The major lateral radula teeth of chitons (Mollusca:Polyplacophora) are one of the hardest and most wear resistant biomineralized tissues known to date. Their hierarchical architecture makes ingenious use of magnetite and a variety of other biominerals.

Do chitons have a shell?

Chitons are flattened, elongately-oval, with eight overlapping dorsal shell plates or valves, bordered by a thick girdle formed from the mantle that may be covered with spines, scales, or hairs.

How are chitons different from other mollusks?

Also, unlike limpets and other snails, the chitons have no tentacles or eyes in the head region, just a mouth and a radula. The shell is so different from those of other mollusks that one might think chitons are segmented (or metameric), but contrary to the general rule, this is incorrect.