Setting up a beak armature

I hung the Beast from Beyond up on my wall at work, and it has got quite a bit of attention.  People seem to think it's a real animal at first glance, and most are rather surprised to learn it's made of paper mache.  I've always said paper mache is an underrated medium.

Recently I discovered Ian Johnston's translation of the Eumenides and after reading the passage where the priestess describes the furies she saw inside Apollo's temple, I got the idea to sculpt a harpy's head.  This, I thought, would be an interesting subject.  So far I've been making an armature to give me the internal structure of the head.

It reminds me a lot of a Corinthian helmet.  This was unintended, but it seems appropriate.

When setting up a head armature, I find it's helpful to break the skull down into its component shapes.  This ball represents the brain case.  Next we have a beak that juts out from the base of the brain case, and a lower jaw underneath that.

Once the basic shapes are securely stuck together it's easy to build up the vague shape of a face, as you can see in the first picture.  This will form the basis for all the facial features.  And here you can see one of the reasons I like paper mache so much: I wasn't happy with the shape of the jaw, so I simply cut it into a better shape with a Stanley knife.

From this angle you can get a better view of the cheekbones and where the eyes will eventually sit.