THE CLASSIFICATION OF ANIMALS 



2O I 





Meso : zo^>vJ'' 



^fcdS^^Hiw 



PfroVoZ ^ 



4 ^- 



j. V 



X^|V ^<X 



FIG. 197. Diagrammatic expression of classification in a genealogical tree. B indicates 

 possible position of Balanoglossus, D of Dipnoi, S of Sphenodon or Hatteria. 



