lateral arm plate fin侧鳍
lateral fin fold侧鳍褶
The sperm tail is composed of axial filament twisted with the lateral fin, and the axial filament is typical 9+2 structure of microtubule.3.
精子尾鞭由轴丝(A)与侧鳍(Lf)缠绕形成，轴丝结构为典型的“9+2”型，侧鳍只位于轴丝的一侧，并围绕着轴丝而扭转。
参考来源 - 瘤背石磺（Onchidium struma）的生物学研究