I was looking at my low altitude chart and lowered it to take a peak at my Garmin 396, which was on top of the dash in front of Steve. Something did not look right. As I glanced up again I saw the head of a snake staring at me. My first thought was it had to be a joke that my wife, Tammy, was playing on me since she knows I am terrified of snakes and that I frequently have nightmares involving snakes. I looked at Steve and then up again at the panel and saw that the glareshield was covered by the snake's body. At that time I tried to use the chart to block my view of the snake so I wouldn't panic and hyperventilate. Steve looked at me and said, "Calm down, don't panic." Our wives, aware that something was amiss, wanted to know what was going on. Steve told them to look at the panel where the snake was slithering down across the yoke on the copilot's side. It worked its way down through the yoke, across Steve's lap and lay in between the two of us with it's head on the center arm rest. Most of its body was on Steve's left leg. Steve said, "Just fly the airplane, fly the plane." All I could do was try not to look at the snake and concentrate on making our descent to 10,000 feet as assigned by JAX Center. The snake laid there for a while and I was able to breathe a little easier since it was not moving. Our wives were on their knees on the back seats wishing they were somewhere else.