946 The American Naturalist. | November, 
tion of the evidence advanced by Cope and other writers that 
change in the forms of the skeletons of the vertebrates first 
appears in ontogeny and subsequently at birth in phylogeny.” 
On April 18, 1896, I formulated the matter in a paper 
before the Academy entitled “A Mode of Evolution Requiring 
neither Natural Selection nor the Inheritance of Acquired 
Characters,’ which has since appeared in Science. Professor 
Baldwin, of Princeton, and Professor Lloyd Morgan, of Uni- 
versity College, Bristol, had at the same time, independently 
reached the same hypothesis, and Professor Baldwin has aptly 
termed it “ Organic Selection.” Both writers have presented 
valuable critical papers upon it, including in Science and Nature 
a complete terminology for the various processes involved. I 
concur entirely in their proposal to restrict the term variation 
to congenital variation, to substitute the term “ modification” 
for ontogenic variation, and to adopt the term “ Organic Selec- 
tion” for the process by which individual adaptation leads and 
guides evolution, and the term “orthoplasy” for the definite 
and determinate results. 
The hypothesis, as it appears to myself is, briefly, that 
ontogenic adaptation is of a very profound character, it enables ani- 
mals and plants to survive very critical changes in their environ- 
ment. Thus all the individuals of a race are similarly modified 
over such long periods of time that, very gradually, congenital 
variations which happen to coincide with the ontogenic adaptive 
modifications are collected and become phylogenic. Thus there 
would result an apparent but not real transmission of acquired 
characters. 
It is a subsidiary question whether this hypothesis is new, 
and a more important one whether it is true and constitutes a 
distinct advance towards the discovery of the unknown factors 
of evolution, or a satisfactory substitute for the Lamarckian 
theory of transmission of acquired characters. 
_* A writer in the Fortnightly Review has given a somewhat extreme illustration 
of the difference between ontogenic and phylogenic progress when he says : 
“Man is still, mentally, morally and physically, what he was during the later 
Paleolithic period.” “The Artificial Factor in Man.’ Fortnightly Review, 
October, 1896. 
