Work found, with species-group names introduced therein:
Clarke, A. H., Jr. 1959. New abyssal molluscs from off Bermuda collected by the Lamont Geological Observatory. Proceedings of the Malacological Society of London 33 231-238, pl. 13. [Stated date: -- Nov 1959.] Pleurotomella (Theta) lyronuclea, see Theta lyronuclea (Clarke, 1959)
