OUR BEST FEATURES 



piracy which seems to have characterized the 

 more remote ancestors of man for countless ages. 

 But up to this point in their evolution true teeth 

 had not been attained by the early predecessors 

 of the vertebrates. 



nosiriL brain 



S/oinalcord 

 notochorcL 



mouth 

 cavity p 



^lllsandfflllslits 



miesiine 



Fig. 59. A Modern Descendant of the Ostracoderms. 



A. Adult lamprey (after Jordan and Evermann); B. Longitudinal 

 section of larval lamprey, enlarged (after Goodrich). 



THE BEGINNINGS OF TEETH 



The ostracoderms as a whole may be transitional 



between the method of "ciliary ingestion " and 



the devouring of living flesh by the existing 



cyclos tomes (lampreys, hags), which Stensio has 



97 



