Life Sciences Division, Royal Ontario Museum, 1960. — 190 p.Scientists are motivated by one basic aim — to find general rooles or laws which help explane observed phenomena, and which can be applied as widely as possible. When I began this study seven years ago, I realised that there might be some regular pattern common to certain reptilian groups, and thas I undertook to analyse systematically the information available fram all reptilian groups. It soon became obvious that there were many superficialy different replacement patterns, as well as different ways of implanting and replacing individual teeth.
What did not appear obvious at the time, and only came over after much work, was the fact that there was a basic plan behind the dentitions of all vertebrares, and that that plan could be traced back in time, through the well-preserved fossil record, to the stem of the tetrapod line, in the Devonian crossopterygian fishes.
