In vertebrates, the mandible, lower jaw or jawbone is a bone forming the skull with the cranium.

In lobe-finned fishes and the early fossil tetrapods, the bone homologous to the mandible of mammals is merely the largest of several bones in the lower jaw. In such animals, it is referred to as the dentary bone, and forms the body of the outer surface of the jaw. It is bordered below by a number of splenial bones, while the angle of the jaw is formed by a lower angular bone and a suprangular bone just above it. The inner surface of the jaw is lined by a prearticular bone, while the articular bone forms the articulation with the skull proper. Finally a set of three narrow coronoid bones lie above the prearticular bone. As the name implies, the majority of the teeth are attached to the dentary, but there are commonly also teeth on the coronoid bones, and sometimes on the prearticular as well.

This complex primitive pattern has, however, been simplified to various degrees in the great majority of vertebrates, as bones have either fused or vanished entirely. In teleosts, only the dentary, articular, and angular bones remain, while in living amphibians, the dentary is accompanied only by the prearticular, and, in salamanders, one of the coronoids. The lower jaw of reptiles has only a single coronoid and splenial, but retains all the other primitive bones except the prearticular.

Evan William Watkins (1882–1956) was a Welsh rugby footballer who played rugby union for Abertillery and Monmouthshire and rugby league professionally for Warrington. He also played cricket for Monmouthshire.

Watkins played rugby union for Abertillery and Monmouthshire. He then joined the professional rugby league, playing for Warrington in 1908. He played cricket for Monmouthshire in the Minor Counties Championship between 1909 and 1911, making 6 appearances.