''Heloplax'' is a genus of worm-like

mollusc Mollusca is a phylum of protostome, protostomic invertebrate animals, whose members are known as molluscs or mollusks (). Around 76,000 extant taxon, extant species of molluscs are recognized, making it the second-largest animal phylum ...

s. Its soft parts are preserved in three dimensions in the

Silurian The Silurian ( ) is a geologic period and system spanning 23.5 million years from the end of the Ordovician Period, at million years ago ( Mya), to the beginning of the Devonian Period, Mya. The Silurian is the third and shortest period of t ...

Herefordshire Lagerstatte; its disarticulated valves are known from other Silurian deposits. It is very bizarre by modern standards; it bears serially repeated units, and has spines. It probably falls somewhere between the aplacophorans and polyplacophora; its valves were composed of aragonite

References

Prehistoric chiton genera Wenlock series fossils Monotypic prehistoric mollusc genera {{Chiton-stub