Cox (1962) gave an excellent historical review of all published works on Haliotis beginning with Aristotle in the 4th century B.C. Because the genus is world-wide there is a great deal of literature including detailed anatomical studies (e.g. Crofts, 1929), studies of larval stages (e.g. Crofts, 1937; Ino, 1952) and ecological studies (e.g. Ino, 1952; Leighton & Boolootian, 1963). Many more papers have appeared since 1963. Abalones have long been a basic food item in the Orient and are gaining appeal as a delicacy in Western countries. As the level of fishing has increased so has research, particularly in Guernsey (United Kingdom), California, Japan, South Africa and Australia. In Guernsey recent work has been done on density and on growth rate (Forster, 1962, 1967). In California, work on abalones has been associated with a five-year study of the decline of kelp beds (Leighton, 1966) and has been concentrated on their feeding habits. In Japan, research is now concentrating on ecology (Sakai, 1962 a-d) and on methods of mass culture (Oba, 1964a, b) and in South Africa and Australia on population dynamics with a view to regulating the fishery (Newman, 1966, 1967, 1968), Anon., 1967). In New Zealand where an export fishery is just beginning, published work is limited to comments on the use of paua-shell by the Maori (Phillipps, 1935), a general ecological study (Sinclair, 1963), and papers on body proportions (Cleaver, 1966) and feeding (Tunbridge, 1967). The Marine Department has carried out other work, as yet unpublished. This thesis is a comparable ecological study of two Haliotis species. It aims to establish basic ecological information for H. iris and H. australis at Kaikoura and to compare the species. Incidental to this are a comparison of some aspects of the ecology of H. iris at Kaikoura with that at Taylors Mistake, and some comments on H. virginea.