The stapedius muscle may be identified. The cochlear duct has taken an upward turn, as seen in the graphic reconstruction of Carnegie Embryo No. 5609. From the external view of the vestibular area, the utricle and saccule can be distinguished by a groove separating an upper and lower portion. The three semicircular canals are distinguishable, anterior, posterior and lateral. The former two join at one end to form a common crus.
Cartilage appears in the otic capsule.
The first branchial groove is now a depression encircled by the future auricle and may be considered the future external acoustic meatus. A constriction begins to appear between the cochlear duct and the saccule- the future ductus reuniens. The cochlear duct is elongated and curled. At one end of each semicircular canal, an ampulla develops as an enlargement of the canal. Maculae develop within the ampullae.