STM check operation

I've been reading the STM papers on Simon PJ's website, but I find that the GHC I'm using (6.5) changes a few things from the paper's descriptions. For instance, "atomic" becomes "atomically" and "catch" becomes "catchSTM". I can't, however, find "throw", and the type signature of "check" has changed. The GHC documentation isn't much help. Is there a discussion, perhaps in a mailing list archive somewhere, that will shed some light on these changes? Thanks, -Rod