Fig. 4. Sclerite engagement and orientation. (A) Sclerite 2 (red, solid fill) is in the engaged position and braced against the ventral meral infolding. Yellow highlighting indicates the area of ventral meral infolding against which the sclerite is braced. The blue dotted line shows the approximate attachment point and orientation of the lateral flexor muscle that engages the sclerite. Shown from the medial side, with the meral-V (v) behind the sclerite. Ventral is toward the bottom of the page and proximal is to the right. (B) A schematic diagram of the engaged and resting positions of sclerite 2. The darkest sclerite (red) is shown in the engaged position with yellow highlighting the articulating surfaces. When the sclerite is released it rotates distally (to left), to rest with the articulating surface hanging outside the animal (circled). This portion of the sclerite is visible in mantis shrimp specimens and hangs between the merus and carpus. Blue dotted lines show the approximate orientation and attachment of the lateral flexor muscle.