... species were found within an hour's walk, whereas the total (10) number found on the British islands did not exceed 66, and the whole of Europe supported only 321. This early comparison ... 1870's, but did not become common in the United States until the 1920's. (10) In the United States, the first third of the twentieth century saw the workweek movefrom 60 hours per week to ... early tools, (10) surveys of paleoanthropological sites, development and testing of broad ecologicaltheories, and advances in comparative primatology are contributing to knowledge about this central...