x PREFACE 



suggest in outline a system of convergence 

 which is capable of further expansion ; and I 

 have made a point, so far as my purview ex- 

 tended, of acknowledging my indebtedness to 

 the work of predecessors and contemporaries. 



The technical expressions which are scattered 

 through the text will be found not to interfere 

 with the comprehension of the whole. They 

 constitute part of the scheme of arrangement 

 proposed for the phenomena of convergence. 

 Phenomena require to be classified after the 

 same manner as animals, rocks and plants ; 

 and the pregnant technical terms are intended 

 to carry this out for future use and reference, 

 not for the bewilderment of the reader. 



This opuscule was planned and the bulk of 

 the manuscript written in Ceylon. After my 

 return to England in the summer of this year, 

 and after the manuscript had been sent to the 

 printer, my attention was drawn by a friend 

 to an important paper by Professor Henry 

 Fairfield Osborn on " Homoplasy as a Law of 

 Latent or Potential Homology " in the American 

 Naturalist, vol. xxxvi., 1902, pp. 259-271. This 

 paper is illustrated by examples of convergence 

 in tooth-structure (dental convergence), and con- 

 tains a valuable exposition of homoplasy from the 

 palaeontological standpoint. The only point in 



