314 THE HISTORY OF CREATION. 
If we examine this parallelism of the three organic 
series of development more accurately, we have to add 
the following special qualifications. Ontogeny, or the 
history of the individual development of every organism 
(embryology and metamorphology), presents us with a 
simple wnbranching or graduated chain of forms; and so it 
is with that portion of phylogeny which comprises the 
paleeontological history of development of the direct ancestors 
only of an individual organism. But the whole of phylogeny 
—which meets us in the natural system of every organic 
tribe or phylum, and which is concerned with the investi- 
gation of the paleontological development of all the 
branches of this tribe—forms a branching or tree-shaped 
developmental series, a veritable pedigree. If we examine 
and compare the branches of this pedigree, and place them 
together according to the degree of their differentiation and 
perfection, we obtain the tree-shaped, branching, systematic 
developmental series of comparative anatomy. Strictly 
speaking, therefore, the latter is parallel to the whole of 
phylogeny, and consequently is only partially parallel to 
ontogeny ; for ontogeny itself is parallel only to a portion 
of phylogeny. 
All the phenomena of organic development above dis- 
cussed, especially the threefold genealogical parallelism, 
and the laws of differentiation and progress, which are 
evident in each of these three series of organic development, 
and, further, the whole history of rudimentary organs, are 
exceedingly important proofs of the truth of the Theory of 
Descent. For by it alone can they be explained, whereas 
its opponents cannot even offer a shadow of an explanation 
of them. Without the Doctrine of Filiation, the fact of 
