Leech is the common name of leech, belonging to leech class. There are 400 ~ 500 species in the world, about 100 species in China, and 89 species have been found.
The main feature of leech is flat spindle shape with many links; The back is dark brown or dark brown, slightly raised, and black spots can be seen after soaking in water, which are arranged in 5 longitudinal stripes; The abdomen is flat and brown. Brown on both sides, slightly pointed at the front end, blunt and round at the back end, with 1 sucker at both ends, the front sucker is not obvious, and the rear sucker is larger; Fragile, easily broken, and the cross section is gelatinous; The smell is slightly fishy.
Most leeches live in fresh water, a few in salt water, and some in land and amphibians. There are species that feed on blood or body fluids, and there are also species that prey on small animals. Leeches common in rice fields are called Japanese medical leeches, which feed on the blood of people, livestock and frogs.
Some leeches live in the forests of Hainan Island and Taiwan Province Province, and they often lurk in the grass and bushes. Leech can be used as a valuable Chinese herbal medicine after processing. In recent years, due to the threat of chemical fertilizers and pesticides to its living environment and predatory capture by human beings, the wild resources of leeches are decreasing day by day. In order to meet the market demand, the artificial breeding industry of leeches has developed rapidly.
Leech is a general term for annelids and leeches. These animals are different from other annelids such as earthworms or nereis, and most of them live a temporary parasitic life in vitro. In line with this lifestyle, leeches have no bristles, and there are suction cups at the front and rear ends, and their muscles are well developed, and their body cavities are divided and filled by muscles and connective tissues to shrink.