one mean polychaete

[hcgeo003 at huey.csun.edu]

I have just returned from Baja where I took my Marine Biology class on a field 
trip. We were about 50 k south of San Filipe ( on the Sea of Cortez side). 
CSUN has a small marine station there.  I want to know if any of the folks 
reading this list has encountered the following.  We were observing inverts 
during low tide and collecting a few which we would identify later. I had a 
crab (Petrolisthes sp.) in a small vial when I turned over a rock and found an 
errant polychaete. I added it to the same vial with the crab and the crab went 
ballistic, just like when you put a octopod in a fish tank with a crab - it 
knew it was in deep trouble.  In less than a minute the crab was DEAD - with 
out even touching the polychaete. Later we found some mucoid-like substance in 
the vial. Does anyone know what the worm exuded that was so deadly to the 
crab?