Besides the cavum was formed by fat granules.there were pigment granules,lysosome and rough endoplasmic reticulum et, furthermore the cytoskeleton was developed.

• 细胞质内有密布的核糖体及空腔，空腔是由脂肪颗粒形成，细胞质中还有有色素颗粒、溶酶体和粗面内质网等，细胞骨架发达。