Final answer:
In crustacean anatomy, the medial and lateral processes on a limb are called endites and exites respectively.
Step-by-step explanation:
The medial and lateral processes on a crustacean limb are called endites and exites respectively. Crustaceans, which are part of the Arthropoda phylum, typically possess limbs that are biramous, meaning they are composed of two branches: the endopod and the exopod. This biramous condition is considered the ancestral state in arthropods. The endite and exite are different parts of these biramous appendages, with the endite being the medial process and the exite being the lateral one. These structures play various roles in the life of a crustacean, including locomotion, feeding, and respiration.