Cruickshank, A. R.2014-12-232014-12-231968None0078-8554http://hdl.handle.net/10539/16112Main articleThe structure of the large laniary teeth of the Lower Carboniferous rhipidistian fish Rhizodu hibberti Ag. is interpreted in terms of a new theory of tooth development. The structure of these teeth is found to correspond almost exactly to that of the synchronomorial scale as defined by Orvig (195 1) and Stensio (1961 ; 1962). These labyrinthodont teeth are thus shown to be composed of many tooth primordia, and are not a single unit of dentine. Some isolated Rhizodus teeth are described in which the entire labyrinthodont structure is missing, leaving an empty space inside the tooth. From this, a non-mechanical tooth removal mechanism is postulated.enrhipidistian fish; teethArticle