Extended data

1, the flower-covered crab, also known as Jiahong and Huagai, is a kind of crab belonging to Arthropoda, Crustacea, Decapoda and Polypodiaceae. Taking the Yellow Sea and Bohai Sea as more producing areas, the crabs produced are all full of fat and fierce in nature, and even more fierce in defense. There are three kinds of crabs, the first is green cover, the second is purple peel, and the third is flower cover. Among them, purple skin is the largest and rarest meat, which is the treasure of red sea crabs.

2. There are 6 teeth on both sides of the front edge and 6 teeth on the forehead edge. There are 1 rotatable and telescopic compound eyes with handles on both sides of the forehead. There are 5 pairs of pectoral feet, and the 1 pair is a pincer foot, which is strong and asymmetrical. The front end is pincer-shaped, the long section is spindle-shaped, and the inner edge has 3 large teeth and several small teeth. Finally, 1 pairs are swimming feet, which are paddle-shaped. The middle 3 pairs are footy, short and hairy.

3, the abdomen is flat, the male body is triangular, the female body is round, and they are all densely furry. The appendage is buried in the abdomen. The individuals, commonly known as flower-covered crabs, have dark green backs of the head breastplate and the pincers' feet. The head breastplate has gray-white or light-brown symmetrical patches, and the outer fingers of the pincers' feet are dark purple and the fingertips are dark black. The back of the foot is light green or light brown, and the lower color is light; The ventral surface is grayish white.

4. In the process of growth, some individuals become darker, their backs are mostly dark purple, their abdomen is slightly lighter, and the plaques on the head and breastplate also disappear, so they are commonly known as red nails; This kind of individuals are large, mostly males, and females are occasionally visible. The head breastplate is generally 5~6 cm long and 7~9 cm wide, and the male is larger than the female.