How to add bones to tongue of Captain Blender

I am going through “Introducing Character Animation with Blender” and in Chapter 5 you have to add the Bones TongueStretch1, 2,3 to the vertex groups. I cannot select the tongue independent from the whole mesh. Does anybody know, how to add these bones to the vertex groups? And then assigning the tongue verts to the appropriate bones?

I solved this problem myself