Slide showing four diagrams of 'Brains of Primates'. Slide shows four diagrams of 'Brains of Primates'. Label under images reads 'Brains of Primates. The largest (lowest figure) is human,; next, that of a chimpanzee; next, that of a macaque monkey; next (uppermost figure), that of a cebus monkey. (The figures are all reduced to the same scale.' Number '77' written on the tape on the top of slide frame. Late 19th - early 20th century