i32 THE STRUCTURE AND LIFE OF BIRDS cuap. 
Fic. 33.--(@) Human ear—diagrammatic ; (4) ear of Owl, after Gadow 3 (c) of 
Thrush, after Retzius. 
c, Columella; cch, Cochlea; &, Eustachian tube; Ex, outer opening of Ear ; 
L, Labyrinth; rg, Lagena; m, Membrane, closing the drum ; , entrance of auditory 
nerve ; NN, Nerve endings; 01, 2, 3, the three Ossicles, Stapes, Incus, Malleus ; 
rt, Pterygoid bone. 
