Most fishes have unstriated rays along the anterior part of the dorsal and ventral edges (leading edges) of the caudal fin. 在大多数鱼类的尾鳍,沿著背侧与腹侧缘的前部具有无条痕的鳍条。在一些鱼中,例如鰕虎鱼其有条痕的与无条纹的软条数量比在鑑定上是有帮助的。
The leading edge is the part of the wing that first contacts the air; alternatively it is the foremost edge of an airfoil section. The first is an aerodynamic definition, the second a structural one.
As an example of the distinction, during a tailslide, from an aerodynamic point of view, the trailing edge becomes the leading edge and vice versa but from a structural point of view the leading edge remains unchanged.