Light micrograph of Purkinje neurons (light blue) in the cerebellum. Nerve cells of the brain act collectively to process information needed for proper cognitive functioning. (Credit: Steve Gschmeissner/Science Photo Library/Alamy Stock Photo)
Segmentation of Limulus polyphemus. Inconclusive evidence indicates that there are 15 segments (6 in the prosoma, 9 in the opisthosoma). The telson (XV) may be a terminal spine that has become articulated and has incorporated the anus into its base.