Evolution: Its nature, its evidence, and its relation to religious thought
CHAPTER IV.
SPECIAL PROOFS FROM THE GENERAL LAWS OF ANIMAL STRUCTURE, OR COMPARISON IN THE TAXONOMIC SERIES.
_General Principles._
_Analogy and homology_--Defined and illustrated by examples-- Wings and limbs--Lungs, gradual formation of, traced in the Taxonomic series--Traced in the Ontogenic series--Examples of homology in plants: tuber, cactus-leaf, acacia-leaf-- Definitions repeated and further explained--Common origin is the only explanation of homology 99
_Primary divisions of the animal kingdom_--True ground of such divisions is ability to trace homology--We take examples only from vertebrata and articulata--Compare to styles of architecture--To machines--To branching stem 107