''Echinochiton'' is an extinct genus of

Ordovician The Ordovician ( ) is a geologic period and System (geology), system, the second of six periods of the Paleozoic Era (geology), Era, and the second of twelve periods of the Phanerozoic Eon (geology), Eon. The Ordovician spans 41.6 million years f ...

chiton Chitons () are marine molluscs of varying size in the class Polyplacophora ( ), formerly known as Amphineura. About 940 extant and 430 fossil species are recognized. They are also sometimes known as sea cradles or coat-of-mail shells or suck ...

s with hollow spines on its margins; these spines, which are unique among the chitons, have a strong organic component and show growth lines.

References

Ordovician molluscs Monotypic prehistoric chiton genera Fossils of the United States {{Paleo-mollusc-stub