While I think this is awesome, and biology teachers all over the world will love it, the transparency rendering is quite terrible.
The problem is that some surfaces are rendered, while others are not, which looks very wierd. You can reproduce the effect by only displaying the skeleton and setting transparency to 50% or so.
There are two generally accepted solutions:
1) To a topological sort and render all triangles back to front
2) Use a so called depth-peeling algorithm to render the scene in multiple passes
Unfortunately, they do neither right now, but there's always hope for the next version.
Personally, I favor 2) since you can offload all the work to the GPU. I had to implement this once for a CAD/CAM system for hearing aids (they are often custom-built, and you want to render the exterior semi-transparent so you can place the battery and electronics inside perfectly, before sending the thing to the manufacturing machine).