the career of the latter, arresting his development in certain directions. This is unfortunately shown in Owen's attitude towards Darwinism; he did not accept the doctrine of the mutability of species, the common descent of every animal and plant from formless or seemingly structureless masses of matter which, through an infinite series of changes, have become modified into the teeming forms that have flourished or that now flourish on this planet, which was satirically termed by Voltaire "le meilleur des mondes possible." But if Owen failed to appreciate the modern doctrine of evolution (he was fifty-five years old when Darwin's Origin of Species was issued), he had published nearly four hundred monographs, books, etc., and, like Priestley in another science, could not conscientiously alter his views. His attitude caused bitter resentment in certain quarters. He made, however, solid and permanently valuable contributions to natural history, and his "monographic work occupies a unique position."
His work on the anthropoid apes, on the Monotremes and Marsupials, on the Apteryx, the Great Auk and the Dodo, on Lepidosiren, on the Cephalopoda, on Limulus, on the Brachiopoda, and on Trichina spiralis, are all of the highest importance. Likewise his work on Darwin's extinct mammal of South America, Toxodon Platensis, "referable by its dentition to the Rodentia, but with affinities to the Pachydermata and the herbivorous Cetacea"; and his other memoirs on the extinct fauna
