The thousands of photographic motion studies Edweard Muybridge made in the middle 1880's, collectively published in 1887 as 'Animal Locomotion', are standard reference works for those interested how mammals move. Such groups would include scientists, artists and, no doubt, voyeurs. Click on the 'Point of Interest' image at right to view a probable source (allowing for artistic license) for the male and female figures drawn on the cover of 'Footholds' by Philip Slater. KB