Contents

20 October 1989
Vol 246, Issue 4928

About The Cover

Wiwaxia corrugata, one of the problematic fossils from the 530-million-year-old Middle Cambrian Burgess Shale of British Columbia. The covering of scales and spines was molted at intervals during growth and provided protection from the numerous predators in this remarkable soft-bodied fauna. See page 339. [Photograph by S. Conway Morris]