Figure 9.

Three consecutive TS views from CAT of Mirounga leonina, in posterio-anteror sequence, from a CAT, showing variation in extension of the paries tegmentalis along the bulla and gradual reduction of the tympanic cavity. (A) Caudal TS, showing the petrosal excluded from the tympanic bullar roof, which is completely formed by the CCLE, and tympanic cavity restricted to a small space. (B) Middle TS, showing a bigger tympanic cavity, with a visible tegmen tympani (TT), and lateral extension of the canalis caroticus (CCLE). (C) Anterior TS, showing a large cavity, recessus epitympanicus that contains the malleus and incus (both large), and tegmen tympani (TT), associated to the lateral extension of the canalis caroticus (CCLE). Skulls in lateral view show the precise line of each TS.