I took The Beast out of its case because it takes up less space this way, and also changing the bobbin required flipping the machine up on its hinges; you can see from the next photo that the bobbin is a Royal Pain to reach.
BTW, I gave everything a nice clean, wipe, and oil, being careful to avoid the fabric-and-metal belt. While I think I will replace a wire in the motor (it looks worn), otherwise things are in amazing shape! It stitches very nicely! Only a straight, reverse, and zig-zag.
So, this next photo shows accessing-the-bobbin.[ATTACH=CONFIG]416047[/ATTACH]
The bobbin case itself is not terribly weird, I suppose; but it does have a funny hook on it, which I have figured out (Miriam ,you are right!) how to thread.