River clam.

River mussels are the collective name for a class of animals belonging to the family Mussels (scientific name: Unionidae) of the phylum Molluscs. They are called clam shells or crooks in some places. They live half-buried at the bottom of freshwater lakes, swamps, rivers, etc. In the mud. The meat is edible and can also be used as bait for fish and poultry and as feed for poultry and livestock.

In some areas, freshwater pearl clams are used to raise pearls. The main species used to raise pearls are the triangular sail clam and the ruffled crown clam. The inlet and outlet pipes at the rear end of the clam body are exposed, and water can flow into and out of the outer mantle cavity, thereby completing functions such as ingestion, respiration, and excretion of feces and metabolites, filtering microorganisms and organic matter particles in the water, and also eating small microorganisms.

Extended information:

Morphological characteristics

The shell shape varies, and the two shells are equal. The carvings on the top of the shell are often concentric circles or polyline shapes, but how many Somewhat degraded. The hinge part varies greatly, sometimes with pseudo-primary teeth. With 1 external ligament. The septal membrane between the gill lobes is intact and arranged parallel to the gill filaments. The posterior part of the outer lobe of the outer gill is healed with the mantle, and there are gill water tubes. The openings of the gills and anus are completely separated by a septum. ?

There is a ligament on the outside, relying on its elasticity to open the two shells. There are muscle marks on the inner surface of the shell where muscles are attached. There are mantle marks parallel to the ventral edge of the shell; there are three muscle marks on the front and upper part of the shell, the largest one is oval, which is the anterior adductor muscle mark; the upper edge of the latter is a small, slightly triangular precontractor muscle mark; the latter is The lower edge is the extensor muscle scar.

There are some differences in body shape between male and female. There is a protrusion on the abdominal edge. This protrusion is related to reproduction and is the temporary residence of the larvae.

Baidu Encyclopedia-River Clam