THE 



AMERICAN NATURALIST 



Vol. XL VI May, 1912 No. 545 



THE CONTINUOUS ORIGIN OF CERTAIN UNIT 

 CHARACTERS AS OBSERVED BY A 

 PALEONTOLOGIST 1 



DR. HENRY FAIRFIELD OSBORN 



Research Professor of Zoology, Columbia University, Curator Emeritus 

 of Vertebrate Paleontology in the American Museum of 

 Natural History, Vertebrate Paleontologist 

 United States Geological Survey 



II. Evidences foe Continuity 

 Abandoning the historical background, we come to our 

 own subject, the origin and establishment in continuity 

 of characters ivhich when established exhibit many of the 

 distinctive features of unit characters, namely, segrega- 

 tion, stability, pure heredity, and possibly, although this 

 has not yet been demonstrated, dominance and recession 

 in successive generations. 



In fifteen previous papers of the writer beginning in 

 1889 25 the observation is repeatedly made that all abso- 

 lutely new characters which we have traced to their very 

 beginnings in fossil mammals arise gradually and con- 

 tinuously. One by one these characters, which are inde- 

 pendently changing in many parts of the organism, at 

 the same time accumulate until they build up a degree of 

 change which paleontologists designate as a "mutation" 



^Osborn, H. P., "The Paleontological Evidence for the Transmission 

 -S99. pp. 561-566. 



249 



