A new hexactinellid sponge, Heminectere rushtoni sp. nov., has been found in an old collection in Keswick Museum and Art Gallery, UK. The species belongs to a long-ranging genus, but is one of very few Dapingian (Middle Ordovician) hexactinellids described to date, and presents additional information on the range of morphological features present in the group. Heminectere is included within the Protospongiidae, the definition of which is here restricted to vasiform or spheroidal, thin-walled hexactinellids with a regular to subregular, quadruled architecture. The specimen, collected in 1884, also shows that there is potential for further discoveries of important sponge material in the Middle Ordovician of northwest England, and highlights the lack of Dapingian sponges as being most likely a result of collection deficiency rather than genuine rarity. Copyright © 2011 John Wiley & Sons, Ltd.