Fig. 5. The morphology of the raptorial appendage of the peacock mantis shrimp. Line drawings are presented adjacent to photographs of the corresponding areas of the raptorial appendage. Proximal is to the right of the page. (A) Lateral view highlights the external, loose articulation between the meral-V (v) and carpus (c; inset). A thin strip of exoskeleton forms the bridge (b) between the meral-V and saddle (s). (B) Medial view shows the internal meral-carpal articulation that functions as a sliding channel joint (left inset). Also visible is the proximal saddle notch, into which the saddle is pushed during extensor muscle contraction in the load phase (right inset). (C) Dorsal view (medial toward top of page) shows the orientation of the lateral extensor apodeme (a, pink) extending from the carpus and running beneath the saddle. The bridge (b) runs dorsally from the lateral meral-V (visible in A) and across to the distal horn of the saddle (visible in B). The medial meral-carpal articulation consists of two adjacent articulations (orange circles); the internal medial meral-carpal articulation is a robust sliding channel joint (as shown in B, left inset). (A–C) Orange circles indicate articulations; gray bars indicate internal buttressing; beige regions are arthrodial membrane; gray regions indicate exoskeleton; yellow coloration represents the saddle (s). m, merus; p, propodus; d, dactyl.