There was pretty much no way I could leave this behind once I had seen it. First, it's amazing! But also, it's been beaten up and lived a life and been mended all over, which has rendered it, for me least, quite a tender, complex, and rather heart-breaking object.
I know that it originally came from NBC television, and would guess it dates to the 50s or 60s. (There is a fun website--Hollywood Gorilla Men--which really digs into the history of gorilla movies and gorilla costumes, specifically.) I think photos best describe the construction and condition, but of note is the fact that the mouth does open and close, baring those remaining teeth when open! (I did not have a hat stand to use for photographing the mask--so the photos with mouth closed were shot of the mask just sitting as it sits on its own; those with mouth open were shot holding it aloft, when the mouth opens on its own. All of this is to say that having a hat stand or even a tall vase turned upside on which to splay this would be ideal!) It is the face--and ears!--that are most fragile; the head itself holds its shape via a hard cardboard hat-shaped form inside.
The mask has been repaired on the inside with what looks like a mix of a few different types of tape, which shows through in a few spots as pictured. It needs to handled somewhat gently, but once set up on a stand, it should be stable and content! 10 1/8" t x 13" w x 14" d.