This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Descent fig. Woodcut depicting the similar appearance of human embryo top and dog embryo bottom from Charles Darwin's Descent of Man Original caption Fig Upper figure human embryo from Ecker Lower figure that of dog from Bischoff org uk itemID viewtype text pageseq See above Public domain PDold The Descent of Man and Selection