The dream of flying has always fascinated humanity. In evolutionary history, the ability to fly has emerged independently only three times: in birds, pterosaurs, and, uniquely among mammals, in bats.

Fins and limbs and fins into limbs : the historical context, 1840-1940 / Peter J. Bowler -- Skeletal changes in the transition from fins to limbs / Michael I. Coates and Marcello Ruta -- A historical ...