Figure 6. The ECF of phocids. A harbour seal (Phoca vitulina) skull rendered semitransparent to show the cochlea (C) and the ECF inside the petrous bone. A, the cochlear disc exhibits a minimal degree of torsion from the rest of the bony labyrinth to make room for the ECF that connects the round window to the inside of the skull. B, plate beneath showing the species where scan quality allowed for reconstruction of the ECF. Species are ordered by similarity according to the PC scores, starting with Phoca vitulina and ending with Vulpes vulpes. The cochlea model used for measuring is coloured blue, the structure addressed as the ECF is coloured orange. Scale = 5 mm. BMJ = bulla-mastoid junction.