240 DARWIN AND PALEONTOLOGY 



which, had he pursued it to its logical sequence, 

 would have brought him to orthogenesis, namely, 

 that variations may not be without direction, but 

 that law may lie among the hidden recesses of the 

 nature of the organism; in other words, Darwin 

 himself frequently professed ignorance of the laws 

 of variation as well as the belief that such laws 

 might be discovered. Paleontology has revealed 

 certain laws of variation, and it is quite con- 

 sistent with the principle that the ancestral nature 

 of the organism limits and conditions variation 

 that I have to record the following interpretation 

 or hypothesis ^ announced in 1902, namely, that 

 the adaptive origins -of certain characters are 

 predetermined by hereditary kinship. This pre- 

 determination may be due to a similarity of 

 hereditary potential in evolution, that is, ani- 

 mals of similar kinship transmit similar poten- 

 tialities in the origin of new characters. There 

 is an ordinal kinship, a family kinship, a generic 

 kinship, etc. This first renders possible the oc- 

 currence of certain new characters, and second, 

 conditions or hmits these new characters when 

 they do occur. For example, in a certain inde- 

 pendent series of extinct animals derived from 

 common ancestors, we can predict where a new 

 cusp or a new horn rudiment will show itself be- 



^ Osborn, H. P. : " Homoplasy as a Law of Latent or Potential 

 Homology," American Naturalist, Vol. XXXVI, April, 1902, pp. 

 259-71. 



The term Homoplasy was wrongly employed in this paper under 

 a misapprehension as to the significance which its author, Pro- 

 fessor E. Ray Lankester, intended to apply to it. 



