[ London ]: [ Macmillan & Co ] 1925. First Separate Edition. -6 pages (last blank). 7 1/2 x 10 3/4 inches. Offprint from Nature, Volume 115, February 7, 1925. Separately paginated (originally 195-199 pages). A worn copy, with browning, creasing and old cellotape repairs (marginal and at the spine). The second example of this offprint that we've seen, apparently issued (?) without the separately printed wrapper found on some publisher offprints. Printed in Great Britain by R. & R. Clark, Limited, Edinburgh. Good. Wraps. 
An offprint of the first published description of the Taung child, now recognized as a significant link in the evolution of modern humans. Found in a quarry by miners, the skull was sent to Prof. Dart by Josephine Salmons (his first female student) who suspected it's significance. Dart agreed, requested more material, and after further analysis quickly published this paper. Unlike the immediate news splash the "Lucy" fossil evoked in the 1970s, Prof. Dart was largely ignored and criticized for his paper, partly because he wasn't part of the scientific establishment. Much skepticism was aired about whether the fossil belong in the human ancestral chain or was part of the chimpanzee/gorilla line.
Many years later Prof. Dart was vindicated and the establishment made clear he had been right: "In 1947, Sir Arthur Keith [ Dart's former mentor ] published in Nature, announcing his support of Dart and Broom's research. He admitted "the evidence submitted by Dr. Robert Broom and Professor Dart was right and I was wrong". Keith admitted that with the new evidence along with the Taung Fossil indicated that this fossil was human-like in posture, dental elements, and its bipedal walk. In early January 1947, at the First Pan-African Congress on Prehistory, Wilfrid Le Gros Clark was the first anthropologist of such stature to call the Taung Child a "hominid": an early human. An anonymous article, published in Nature on 15 February 1947, announced Clark's conclusions to a wider public. On that day, Keith, who had been one of Dart's most virulent critics, composed a letter to the editor of Nature announcing that he supported Clark's analysis: "I was one of those who took the point of view that when the adult form [of Australopithecus] was discovered it would prove to be near akin to the living African anthropoids—the gorilla and the chimpanzee. I am now convinced... that Prof. Dart was right and that I was wrong. The Australopithecinae are in or near the line which culminated in the human form" (wiki)
Even with significant advances in technology and science, the discovery is still recognized as significant. Dean Falk, the American evolutionary anthropologist notes in her "The Fossil Chronicles: How Two Controversial Discoveries Changed our View of Human Evolution, Berkeley and Los Angeles: University of California Press, 2001" that this discovery is "the most important anthropological fossil of the twentieth century."
An important paper, one under appreciated in the collecting community. In November 2019, Nature magazine included this paper in a new list of the ten most influential Nature papers of all time.
Scarce, with only 2 copies of the offprint noted in OCLC (Acc# 26585318). The rarity of the offprint isn't surprising given the article's initial reception in the scientific community.