Unpublished figure, 'Diagram to represent the formation of Crossopodia' by Henry Alleyne Nicholson Two drawings in pencil, labelled figure 5, representing a section of stratum showing on its upper surface the actual trail of the worm, consisting of a central groove and two lateral elevations or ridges, and cast of the same on the lower surface of the bed, showing a central ridge with two lateral depressions. Subject: Palaeontology 1872