Crab and shrimp are about 100mm long and only 20-30mm in size. The breastplate of the head is flat on the side and the forehead is a wide and short triangle. There are granular gaps in the back bulge, and short hairs are densely distributed around the bulge. The neck groove is in the middle of the head breastplate, and there is a 1 thorn in the front edge of the head breastplate. All the feet are covered with thick hair. 1 step, the foot is chelated, and the male is larger. There are small teeth on the dorsal and ventral sides of the metacarpal joint, and 1 mucro on the dorsal edge of the wrist joint.
Crayfish are caught in late summer and early autumn, and most of them stay in mud after low tide. Fishermen can dig and scratch with shovels on the beach, and of course there is a more interesting way of sea fishing-using a writing brush.
The fisherman found a mole shrimp in the hole and slowly put the brush into the hole. When mole shrimps feel foreign objects entering, they instinctively raise their claws to resist and tightly clamp the hair on the brush. The fisherman will take this opportunity to slowly lift the pen, and a mole shrimp will be hung on the brush. Fishermen who make good use of methods can get a bumper harvest in a day's tide.