Gyraulus corinna Gray, 1850 Length 3.3mm, Width 2.6mm, Height 0.8mm, Freshwater, North Island, South Island, Endemic. Four slowly increasing whorls North and South Island N.S.E.
Gyraulus kahuica Finlay & Laws, 1931 Length 6mm, Width 5mm, Height 1.75mm, Freshwater, North Island, South Island, Endemic. Much larger than G.corinna, 3.9-6.0 mm in diameter, yet with only 3-3.5 whorls, which are more accellerated North and South Island N.S.E.
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