Descendant, Descending

French: en descent

The term is used for any beast borne as it were descending.

gu a dove descending

A dove volant depicted in its flight downwards, bendwise with the back part to sight.  

a lion descending from sinister chief to dexter base point

A lion with the hind legs towards one corner of the chief and the head to one of the base points, as if leaping down from some eminence.

an eagle descendant displayed

When blazoned descendant displayed, the eagle is depicted palewise in its flight downwards.