Why can't I attach skins to my creature?

I am trying to attach skins to my creatures legs. I have been able to do it to the upper left leg but when I try to select the vertices for the upper right leg the other half of the body doesn’t show the vertices. I have attached the file. Any help would be great.
I am very new to Blender.

Attachments

creature_animated.2blend.blend (166 KB)

You have a mirror modifier. You’llhave to apply it to rig correctly.

Its really subsurfed alot . I think if you remove 1 or 2 and t key then smooth it will look the same.