Columbia University
Columbia University: Thomas Hunt Morgan
The site promotes the importance of Morgan and his experiments in genetics with fruit flies on the field of biology.
Talk Origins Archive
The Origin of Species, Chapter 14
The entire text of Charles Darwin's book, The Origin of Species is available on this site. This link is specifically for the chapter that discusses embryology as evidence for evolution.
New York University
Nyu: Darwin's Evidence for Evolution: Embryology
Concise description of embryology as evidence for evolution, as used by Darwin.