Original sentence: (1831–1904), who had developed a rival "causal-mechanical theory" of human embryonic development.Haeckel's theory and drawings were criticised by his contemporary, the anatomist Wilhelm His Sr
Edited sentence: Haeckel's drawings misrepresented observed human embryonic development to such an extent that he attracted the opposition of several members of the scientific community, including the anatomist Wilhelm His, who had developed a rival "causal-mechanical theory" of human embryonic development