Abstract: A finned phalangeal device includes a plurality of spacially disposed, phalanges. On each phalange, a longitudinal flexible fin element is attached on the back side while allowing the longitudinal margins of each flexible film element to extend normally toward a like element on an adjacent phalange. When the device is moved in one direction through a fluid the flexible fin elements feather against the phalange and allow the fluid to pass between adjacent phalanges with relatively little resistance. When the device is moved in the opposite direction the flexible fin elements open to adjacently overlay each other and hence to provide a fluid seal inhibiting fluid flow between adjacent phalanges. In one embodiment the phalanges are integral members of a glove and specifically are finger encircling elements thereof while in another embodiment each phalange is a rigid prosthesis element simulating those fingers.