Stem margins are shallowly through deeply crenate and undulate. The leaves grow in whorls, and are undulate, shiny, and oblanceolate. Its grey-green leaves are wavy (undulate), oblong to elliptical in shape, usually long by wide. "Agave univittata" has thick, fleshy leaves that are stiff and undulate (wavy) along the margins. In balistiform locomotion, both anal and dorsal fins undulate. The 3-4 leaves are glaucous and undulate. Metallic-mesh triangular screens undulate across the ceiling to hide catwalks. Streamlined fish, such as salmon, undulate the caudal portions of their bodies. Eel-shaped fish undulate their entire body in rhythmic sequences. The leaves are simple or undulate, covered with stiff hairs. Dinsdale dismissed the hypothesis because eels undulate side to side like snakes. The arrow worms (chaetognatha) undulate their finned bodies, not unlike fish. In short, the current ought to "undulate" in sympathy with the oscillations of the air. When diving under water, they undulate their bodies and tails. These tails undulate periodically, which gives a Zora's head the unique semblance of a fish.