Fig. 5. Endoscopic images illustrating a typical sequence observed during feeding on pellets off a gravel substrate (30 frames s^-1; duration of sequence 267 ms). The anterior of the fish is to the right. The palatal organ (po) is visible above rows of gill rakers on ceratobranchials I—III (cb I—III). (A) A pellet (pe) is observed entering the field of view and being pinned across cb III by an overall height reduction of the pharyngeal slit. (B) A rock (r1) enters the field of view, followed by (C) a second rock (r2) and (D) a third rock (r3). (E) r2 is pinned across cb II by an overall height reduction of the pharyngeal slit, preventing further posterior movement. (F) r2 is released by the palatal organ. (G) r3 has moved anteriorly out of the field of view during a spit, and r2 moves further anteriorly. (H) r2 almost completely leaves the field of view in an anterior direction. r1 is visible again behind r2. (I) r2 is spat anteriorly out of the field of view while the pellet and r1 remain pinned across cb III. r1 exited anteriorly from the field of view in the subsequent frame, while the pellet was retained by a palatal protrusion. Movie available online (movie: fig5.mov).