1. Gills: in the place where the crab breathes. There may be mud, sand and other ingredients in this place.

2. Crab heart: the part of crab heart is in the middle of the crab's yolk

3. Crab stomach: there is a bony place, similar to a small bag, which is the crab's stomach

4. Crab intestines: crab intestines are in the crab's triangular area, and there are also a lot of crab excretions in this part of the crab