The cuttlefish is a type of squid. It is the only squid (as far as I know) that has a bone in it. It's it not a bone like in our skeltons. The outter part is a thin, but hard shell kind like a fingernail. The inner porton is soft and chaulky. It's the inner portion that is used by the birds to shapen their beaks.
Here is a picture of the inner portion.
Here's a pic of a bunch of them. You can sort of make out the back or outter side.
And here's what the little critter looks like.
I had birds as a kid. Lucky me, I lived by the sea and could go pick up the bones for free!