acicula

复数：aciculas

n.a needlelike part or structure of a plant or animal or crystal; as a spine or bristle or crystal

1. The polychaete worm uses its acicula to support its parapodia.
   多毛虫用其刺状体支撑疣足。
2. Aciculae are crucial for the movement of certain annelids.
   刺状体对于某些环节动物的运动至关重要。