Columbia subject headings:
Harvard subject headings:
Evolution (Biology)
Mammals, Fossil.
Paleontology.
Phylogeny.
Simpson, George Gaylord, 1902-1984
Vertebrates, Fossil
Vertebrates--Evolution
Princeton subject headings:
Mammals, Fossil.
Paleontology.
Phylogeny.
Simpson, George Gaylord, 1902-1984.
Vertebrates--Evolution.