UCMP MYSTERY FOSSIL #32 is . . .
Canadia

Canadia is a polychaete, a segmented marine worm, from the Burgess Shale of British Columbia. All polychaetes have an array of bristles on their leg-like parapodia. Of the 9000 or so known species of annelids, more than 8000 of them are polychaetes. Find out more about polychaetes here.