“…Raup, 1967;Vermeij, 1971;Davoli & Rosso, 1974;Graus, 1974;Kohn & Riggs, 1975;Newkirk & Doyle, 1975;Warburton, 1979;Cameron, 1981;Verduin, 1982;Ekaratne & Crisp, 1983;Saunders & Shapiro, 1986;Tissot, 1988;Foote & Cowie, 1988;Johnston, Tabachnick & Bookstein, 1991;Emberton, 1994;Clarke, Grahame & Mill, 1999;Samadi, David & Jarne, 2000). Surprisingly, all the other shell models, many of which produce more realistic forms, have received very little attention as compared to Raup's model (see e.g.…”