Question about Cystoids and their food catching/feeding mechanism

[Sallent]

I bought this fossil the other day. It is two cystoids from the middle Cambrian, apparently from Idaho. I was looking for more information as to how they caught their food, perhaps their mouth/digestive processes. I seem to find a lot more about crinoids than I do these guys. Part of my curiosity is that I've seen fossils of crinoids with rather well-preserved tube arms showing decently sized pinnules to catch floating food particles, however, the few pictures of cystoid fossils I've come across seem to show thin arms and I can't really see any pinnules preserved. It just kind of peaked my curiosity about how these guys would have caught their food and transported it to their mouths.  I also can't seem to find any pictures of fossils showing the mouth structure of these creatures.

 

I'm relatively new to fossils, so any help is appreciated. I'm sure someone is bound to know more about these things or have a fossil that shows these things in more detail. Any help is appreciated.

 

[doushantuo]

look like gogiids to me

BTW:

 

liidscolourgeag+p27.pdf