哺乳动物只含有球囊和椭圆囊两种耳石器官，而非哺乳动物中还存在另外一种耳石器官——瓶状囊。

The macula lagena is another otolithic organ in the inner ear of non-mammals, and the lagena of more advaced birds develops better than that of lower animals.

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到胚胎第15天，椭圆囊、球囊、壶腹峪初具成熟形态，毛细胞和支持细胞也初具雏形，到出生时，前庭器官已基本发育成熟。

The shapes of utricle, saccule and crista ampullaris tended to mature at E15, and the shapes of supporting and hair cells also tended to mature. The vestibular organ was mature at P0.

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到胚胎第15天，椭圆囊、球囊、壶腹峪初具成熟形态，毛细胞和支持细胞也初具雏形，到出生时，前庭器官已基本发育成熟。

The shapes of utricle, saccule and crista ampullaris tended to mature at E15, and the shapes of supporting and hair cells also tended to mature. The vestibular organ was mature at P0.

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