Undulipodium (pl. undulipodia) A whiplike organelle that protrudes from a eukaryotic cell and is used chiefly for locomotion (e.g. motile gametes) or feeding (e.g. ciliate protoctists).

波足（生毛）：细胞表面突起的鞭结构，主要作用为运(：精子)和摄食(：纤毛protoctists)。