Central to the curvature of the front half of the corpus callosum can be seen the laminae of the "septum pellucidum." These are two thin plates of gray and white matter that extend on each side between the corpus callosum and another curved, flattened bundle of white
muscle fibers, called the "fornix."
http://www.innerbody.com/image_nerv02/nerv84-new.html
nice dialogue with you outlaw, amybe that natural well driniking
of course this is wild speculation and i might just be contracting the eye changing its shape