I can't find subsurb button.

I am very new in Blender. I am using Debian Sid and my blender version is 2,46. I am working with this book. http://www.blender.org/documentation/htmlI/x1244.html.

Everything went well until I came the subsurb button on mesh pannel. I couldn’t find it and I don’t want to omit anything. First picture from book and second from my blender.

http://img411.imageshack.us/img411/5879/res1yk6.jpg

http://img355.imageshack.us/img355/7950/res2fz0.jpg