Here are some videos on how to collect, extract and then treat specimens.
First, sediment has to be collected - this can be done with different methods. For worm burrows in the intertidal, a "slurp gun" can be used:
This video show how to make an extraction of meiofauna with magnesium chloride
http://www.youtube.com/watch?feature=player_detailpage&v=kEbRl98u0Io
After the extraction, we sort out acoels:
and if we are lucky we find many of one species alone: