Social Control of Primary Sex Determination in the Midas Cichlid

A lumber stacker comprising a vertical frame provided with a feed elevator on the front end of the frame which delivers short stacks of boards to a horizonal advancing conveyor on the upper portion of the frame and on which a layer of such stacks accumulates to a predetermined amount when a horizontal elevating frame raises to lift the accumulation of stacks from the advancing conveyor and places them on a horizontal projectable supporting plate which is moved past the rear of the frame and is lowered by downward movement of the elevating frame onto a supporting surface or top of a stack being formed, after which the supporting plate is retracted onto the elevating frame from beneath the accumulated layer of stacks and returns to the initial starting position.