The animal I have used as forward and back buttons in this exhibit is
Marella Splendens, also known as the "Lace Crab".
Marella is the most common fossil at the Burgess shale, though it is, apparently,
absent from the earlier Changjieng site in China. Like the other Burgess
shale animals, Marella shows up as a black carbonaceous film on the black
shale. It is classified as an arthropod in its own order, as the number
of its appendages does not fit in present day orders.
It may have been able to swim, but since it was flushed over the cliff in
such large numbers it must have stayed close to bottom. Perhaps it was like
present day crawfish, able to shoot off in a cloud of silt if disturbed,
but making its living scavenging on the substrate.
Details of painting by D.W. Miller from American Scientist, March-April, 1997. Labels added