SENSE ORGANS OF BIRDS—PUMPHREY 321 
&y, 
EE. Se ap: a AX 
IR Goll eae 
Ni Mae DUSvsUEUNsaoweceucaemeauaeuacenouraneat! 
. . 
Sit: 
Membrana tectoria 
Figure 9.—A, Diagrammatic section of bird’s ear. 0. m., basilar membrane; col., columella; 
e. c., extra-columella; E. ¢., Eustachian tube; f. r.. round window; h., helicotrema; h. ¢. C., 
hair cells of Corti’s organ; h. c. l., hair cells of lagena; sacc., sacculus; s. ¢., scala tympani; 
5. v., scala vestibuli; ¢. m., tectorial membrane; ¢. v., tegmentum vasculosum; tym., tympanic 
membrane. B, Diagrammatic section across avian cochlea. G. cochl., cochlear ganglion; 
s. m., scala media; other lettering as in A. C, Central part of B enlarged. (After Satoh, 
1917.) 
