Blender 2.55 - Thickness of strands


I am playing arround with hair particle system.
Is there any way how to change the thickness of strands somehow?
Further more where I can set the start thickness and end thickness?
How can I control the thickness more detailed? E.g. at start big in the middle thin and at the end big again?

I am using Blender 2.55

Thanks for any hint!

In Material Panel you have the Strand subpanel. Tha last slider there “Shape” gives the shape but the one you want I think not is one of them (look in the wiki for blender 2.49 to see the shapes)