Just a couple of skeletons that I drew when I was working out body structures and such.  I wasn’t super happy with the skyborne skeleton itself, but it was close enough that I never bothered to draw another one.  It does show pretty clearly the wing finger and the structure behind their chest muscles, even if it’s not totally accurate.  I was originally planning to draw the structure of their feet as well, but I ran out of room on the page, as you can see.

I was happier with the squirrel skeleton.  It looks pretty much like a six-legged quadruped/sextuped would, I think.  And I added the sketch of the squirrel itself in that space up top, just to make certain I could get the posing right – this was the only concept I did for them, after all.