Mysticeti

例句：

1. 1. The Mysticeti are a group of ancient creatures that were believed to have existed in the world before humans.
   神秘生物是一群古代生物，人们相信它们在人类出现之前就存在过。
2. 2. In folklore, the Mysticeti are often depicted as beings with magical powers and abilities.
   在民间传说中，神秘生物通常被描绘成拥有神奇力量和能力的生物。
3. 3. Some scientists believe that the Mysticeti may be related to modern-day dinosaurs, but their exact origins remain a mystery.
   一些科学家认为神秘生物可能与现代的恐龙有关，但它们的确切起源仍然是一个谜。