Heloplax

{{Short description|Extinct genus of molluscs}}

{{Speciesbox

| genus = Heloplax

| species = papilla

| authority = Cherns, 1998

}}

Heloplax is a genus of worm-like molluscs. Its soft parts are preserved in three dimensions in the Silurian Herefordshire Lagerstatte; its disarticulated valves are known from other Silurian deposits.{{Cite journal| first1= M. D.| first2 = D. E. G.| first3 = D. J.| first4 = D. J.| last1 = Sutton| last2 = Briggs| last3 = Siveter| last4 = Siveter| title = Computer reconstruction and analysis of the vermiform mollusc Acaenoplax hayae from the Herefordshire Lagerstatte (Silurian, England), and implications for molluscan phylogeny| journal = Palaeontology| volume = 47| issue = 2| pages = 293–318| year = 2004| doi = 10.1111/j.0031-0239.2004.00374.x| bibcode = 2004Palgy..47..293S| s2cid = 84577088| authorlink2 = Derek Briggs}}

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