212 The American Naturalist. [March, 
this energy with others which are present in the organism or 
in the environment, or both. Ryder has called the exhibition 
of growth energy Ergogenesis,‘ and he calls attention to the fact 
that it appears under two aspects. In the first, Ergogenesis is 
due to mechanical causes resident in the organism exclusively, 
and it expresses the sum of the bathmic energy inherited from 
the parents of the growing organism. To this conservative ex- 
pression of Bathmism he gives the name of Statogenesis. In 
the second aspect of Ergogenesis, the course of growth (onto- 
geny) is determined by motion from sources external to the 
germ cell. It is this which modifies ontogeny and produces 
those changes of structure which constitute Evolution. To this 
aspect of growth I have given the name Kinetogenesis’ As 
Statogenesis expresses simple growth force, and Kinetogenesis 
the additional growth, which is evolution, the latter is chiefly 
considered here. 
Kinetogenesis is of two kinds; viz., the changes in growth 
which are due to the interference of molecular energies only, 
and those which are due to molar movements. The former 
type of evolutionary growth I propose to call Physiogenesis; 
and I propose to restrict the term kinetogenesis to the latter class. 
To the total evolutionary energy or energies due to external 
interference, the Kinetogtnesis of Ryder, I propose to apply 
the term Bathmogenesis. The relation of these modes, an 
their corresponding names may be expressed as follows: 
Statogenesis 
Bathmogenesis. Physiogensis. 
Ergogenesis { 
Kinetogenesis. 
Statogenesis, I shall hereafter endeavor to show, is an auto- 
matic product of Bathmogenesis. ` h 
The first step in the order of Bathmogenetic action 1s ie 
effect of stimuli on an animal which is no longer protected bY 
the parent or by parental products (egg-shell) as an a 
Changes may be effected in the weight, color, and in function 
* Proceeds. Amer. Philos. Soc. 1893, p. 194. es 
° Origin of the Fittest, 1887, p. 423. Statogenesis and Kinetogenesis are eq 
valents of my Growth Force and Grade Growth Force, Proceeds. Amer. 
1871, p. 258. 
