epurals In fish larvae, flattened bones along the dorsal side of the urostyle. Those on the ventral side are called hypurals. From these bones the caudal fin rays arise.

• 尾骨在仔鱼中，平的硬骨沿著尾杆骨的背面两侧。在腹的侧边上的那些被称为尾下骨。从这些硬骨上延伸出尾鳍鳍条。