9407826 McLoon ABSTRACT The extraocular muscles, the muscles that move the eye in the orbit, are different from other mature skeletal muscles in mammals. They have a number of characteristics seen only in immature or regenerating muscle, such as the continued expression of immature or embryonic proteins and as well as immature patterns of innervation. This study proposes to examine the possibility that either these muscles fail to fully mature or that the extraocular muscles, unlike other skeletal muscles continue to divide in the mature mammal to produce new muscle fibers. This will hopefully shed light on possible mechanisms that control when and how muscle cells divide.