Re: could trilobites still survive deep in the ocean?

Because there have been many discoveries in the depths of the World's 
oceans I cannot completely rule out the possibility that some species of 
trilobite (possibly highly modified for deep sea life) could still live 
there.  Some fossil species did live in the deep sea, however, most 
trilobites were probably relatively shallow water forms.  To make a long 
answer short- probably not, but we don't know for sure!

I recommend:

Subphylum Trilobita: http://www.earthlife.net/inverts/trilobita.html

This site has some book references that you also might find interesting!