Green’s Dictionary of Slang

mumming crib n.

a theatre.

1844		New Sprees of London 3: I'll introduce you to [...] the Lushing, Chanting, and Night-cribs, Bawdikens, Hells, Boosing, and Lightning-cribs, Mum- ming Caseys where you may ddoss lush, or feed.
1844		New Sprees of London 13: The Theatre Royal, or otherwise, the mumming crib, lessee, John Douglass.