Morley, M.S., Hayward, B.W., Raven, J.L., Foreman, G.A., Grenfell, H.R. 2006 Intertidal and shallow subtidal biota of Mahia Peninsula, Hawkes Bay, Records of the Auckland Institute and Museum, 43 (p.33)
Powell, A.W.B. 1979New Zealand Mollusca: Marine, Land and Freshwater Shells, Collins, Auckland (p.108)
Key to Geographical Ranges
The symbols K.A.C.F.M.An. are used to indicate the geographical range of the species.
They have been adopted to give an approxomation of the range of each species within New Zealand.
Aupourian - Kaipara Harbour, north around North Cape, encompassing the Three Kings Islands and south to East Cape
Cookian - Lower North Island and the northern part of the South Island