MORPHOLOGY OF ANIMALS 



Fig. 27. Human Ear. A, Internal Ear, sensory portion, infolded from ectoderm of embryo ; 

 u, utricle ; s, saccule, cd, cochlear duct ; asc, anterior-vertical semi-circular canal ; psc, 

 posterior-vertical semi-circular canal. B, Section through Ear; em, external auditory meatus; d, 

 ear drum ; os, 3 ossicles or chain of bones across tympanic chamber, t ; e, eustachian tube ; 

 ph, pharynx; fr, foramen rotundum ; fo, foramen ovale; sc, vertical semi-circular canal; c, 

 cochlea; sm, scala media or cochlear duct; an, auditory nerve. (After Tschermak). 



