File:Rstb20140313f01.jpg

English: Figure 1. Opabinia regalis Walcott, 1912; USNM 155600 preserved in lateral view. (a,b) Counterpart ‘flipped’ horizontally to match (c), Whittington's [1, fig. 35] composite explanatory drawing of the part and counterpart; (a) is illuminated from a low angle and (b) from a high angle to generate reflection in the eyes, for example, showing the method Whittington used to illustrate different features of the Burgess Shale specimens. The needle-marks evident in (a) show where Whittington prepared the specimen to reveal the terminal spines on the ‘flexible frontal process’ or proboscis which is flexed backwards underneath the body. (c) Whittington's camera lucida drawing and interpretation. L and R indicate features on the left and right sides of the body; i and o, inner and outer eyes; l, lateral lobes of the trunk, numbered from the anterior; f, blades of the tail fan; ds, dark stain representing material that has ‘leaked’ beyond the body.