ABSTRACT
The ear capsule chondrocytes are derived from three sources, viz. neural crest, ear placode and surrounding ectoderm, and also cranial mesentoderm.
Under experimental conditions the crest ectomesenchyme is the least significant and the placode the most important source of cartilage cells.
Ectomesenchyme of placodal origin predominates more often in capsules which developed into normal structures than in those that developed somewhat abnormally.
The cartilaginous wall separating the internal ear from the brain is essentially of axial origin although it receives a contribution from the ecto-mesenchyme.
Axial and capsular cartilage is separated along a fairly definite line ventral to the medial wall of the capsule.
The presence or absence of the ear capsule affects the shape of the foot-plate of the columella, but not its existence.
The footplate and stylus columellae share an origin with the visceral skeleton.
The columella is most likely a part of the hyoid arch.