Value ! is not a member of Actor

I've got an Actor class that manages a list of Actors. When it receives a message of a certain type, it passes it off to each of the Actors it knows about.

 var loggers : List[Logger]    

def receive = {
  ...
  // log request
  case logmessage : LogMessage => {
      // send message to each logger (if none, nothing happens)
      for (logger <- loggers)
        logger ! logmessage
  }
  ...     
}

I'm getting a compile error on logger ! logmessage : "value ! is not a member of (package).Logger". The ! makes this very difficult to google. The Logger class compiles, having its own receive method, one line including self ! PoisonPill, meaning the ! operator works there. They're in the same package.