amature missing

I am learning Blender 2.45 with the 2.3 guide. I am rigging a character and after placing all the bones and selecting them all one of them is missing in the armature bones button box. If i select that bone itself it will show. Why is that? Have I done something wrong or is there a limit on how many bones the menu box will list at a time?

there is a limit to how many bones will display at a time. You can discuss whether it is good or bad, but it was done apparently to avoid things slowing down.