The crab's stomach looks like the following picture:
Crab morphological characteristics: the crab's body is divided into cephalothorax and abdomen. The back of the cephalothorax is covered with cephalothoracic armor, the shape of which varies from species to species. The center of the forehead is equipped with the 1st and 2nd pairs of antennae, and on the outer side are compound eyes with stalks. The mouthparts consist of 1 pair of large jaws, 2 pairs of small jaws and 3 pairs of jaw feet. Cephalothoracic armor flanked by 5 pairs of thoracic feet. The abdomen is reduced, flattened and curved on the ventral surface of the cephalothorax.
Male abdomen is narrow and long, mostly triangular, with only the first two pairs of appendages deformed into copulatory apparatus; female abdomen is broad, with one pair of double-branched appendages in each of segments 2-5, densely covered with bristles, used to hold eggs. Most crabs are marine, with tropical shallow sea species being the most abundant.
Expanded Information
Crab Nutrition Facts: Each hundred grams of crab contains 95 calories, 13.8 grams of protein, 4.7 grams of carbohydrates, 2.3 grams of fat, 260 mg of sodium, 232 mg of potassium, 208 mg of calcium, 142 mg of phosphorus, 125 mg of cholesterol.
47 milligrams of magnesium, 3.32 milligrams of zinc, 2.99 milligrams of vitamin e, 2.5 milligrams of niacin, 1.67 milligrams of copper, 1.6 milligrams of iron, 0.18 milligrams of manganese, 0.1 milligrams of riboflavin, 0.01 milligrams of thiamine, 82.65 micrograms of selenium, and 30 micrograms of vitamin a.
Crab Habits: a small portion of the crab species grows and reproduces exclusively in fresh water , and they mostly inhabit under the rocks of mountain streams. There are also a few crabs such as the ground crab can adapt to land life, burrowing in moist mud holes, and migrate to the sea during the breeding period.
The vast majority of crabs are omnivorous. Some crabs are carnivorous, such as pike crabs can prey on fish, shrimp and mollusks. A few crabs, such as the stranded window crab, scrape or filter feed on algae and organic debris.
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Baidu Encyclopedia-Crabs