CLASSIFICATION AND CREATION. 43 
the past, then it is well that all should share in 
its teachings, and that it should not be kept, like 
the learning of the Egyptians, for an exclusive 
priesthood who may expound the oracle accord- 
ing to their own theories, but should make a, part 
of all our intellectual culture and of our com- 
mon educational systems. With this view, I will 
endeavor to simplify as far as may be my illus- 
trations of the different groups of the Animal 
Kingdom, beginning with a more careful analysis 
of those structural features on which classes are 
founded. 
I have said that the Radiates are the lowest 
type among animals, embodying, under an infinite 
variety of forms, that plan in which all parts bear 
definite relations to a vertical central axis. The 
three classes of Radiates are distinguished from 
each other by three distinct ways of executing 
that plan. I dwell upon this point; for we shall 
never arrive at a clear understanding of the dif 
ferent significance and value of the various 
divisions of the Animal Kingdon, till we appre- 
cigte the distinction between the structural con- 
ception and the material means by which it is 
expressed. A comparison will, perhaps, better 
explain my meaning. There are certain archi- 
tectonic types, including edifices of different 
materials, with an infinite variety of architec- 
tural details and external ornaments; but the 
