The oyster is the shell of oyster, oyster, oyster and Dalian Bay oyster, etc. The oyster, oyster and Dalian Bay oyster are distributed along the coast of China. The oyster is distributed along the coast of China, and the Dalian Bay oyster is distributed along the northern coast of China. 1. The oyster is round, ovoid, triangular, or slightly longer, with a thick shell and a long shell, the larger one is 100-242mm in length and 70-150mm in height, and the left shell is larger and thicker, with the back as the attachment surface and irregular shape. The right shell is slightly flattened, the surface is ringed with thin and straight scales, yellowish brown or dark purple, 1-2 years old individuals, scales are flat, thin and brittle, sometimes the edge is free; 2 years to several years old individuals, scales are flat, sometimes the posterior edge is undulating and slightly watery; perennials, the scales are laminated, very firm and thick. Inner surface of shell white or grayish white, margin often grayish purple, uneven, hinge not toothed, ligament grooves long and wide, such as ox horn shape, ligament purple-black. The closed shell muscle scar is very large, located in the middle of the dorsal side, light yellow, irregular shape, often with the change of shell shape, most of them are ovoid or kidney-shaped.　2. long oyster, the shell is long, thick, general shell length 140-330mm, height 57-115mm, length than the height of about three times larger, the largest known up to 722mm. left shell slightly concave, the top of the shell attachment surface is small, the right shell is flat as a cover, dorsal and ventral edges are almost parallel to the surface of the shell lilac, grayish-white or yellowish-brown. The surface of the shell is lavender, grayish white or yellowish brown. The scales are sparsely arranged from the top of the shell to the posterior margin in an annular pattern, slightly undulating, with few layers and no obvious radial ribs. The inner surface of the shell is porcelain white, the ligament groove is long and wide, and the scar of the closed shell muscle is large, located at the back of the shell on the dorsal side, and it is in the form of a brownish-yellow horseshoe.　3. Dalian Bay oyster, shell slightly triangular, shell thick, generally shell length 55-63mm, width 95-130mm, the top of the shell, to the rear edge of the gradual widening. The right side of the shell is flattened, like a cover, and the scales at the top of the shell tend to heal and are thicker; the scales at the ventral edge are lax and undulating, and there are no significant radiating ribs. Shell surface yellowish, mottled with purple-brown spots, left shell protruding, with several stout radial ribs from the top, scales on marginal ribs firm and thickly arched. Shell inner and concave as a hinge, white, hinges small, ligamentous grooves long and deep in long triangular shape. Closed-shell muscle scar white or purplish, situated behind the back. Oyster - salvage 4. dense scale oyster, shell is round or oval, shell thick, generally 46-122mm long, 58-138mm high. left shell is larger and concave depression, the top of the shell for the attachment surface, the shape is often irregular. Right shell top scales fused, smoother, gradually to the ventral edge of the scale ring densely, thin, brittle flaky, to the imbricate tightly arranged, there are a number of radiating ribs, so that the ventral edge slightly undulate, shell surface grayish blue mixed with purple-brown. The inner surface of the shell is white, slightly pearly. Hinged part often with 1 row of small teeth on both sides, about 5-8. Ligament grooves shorter, triangular. Closed-shell muscle scar is larger. Irish rock oyster Oyster flavor is strong. The oyster flavor is brought out by the taste of white wine after sipping a sip of white wine in the mouth. Feel the strong oyster flavor permeating around the teeth.　Scottish golden shell stone oyster Salty taste of seawater first, then the taste of seawater faded, the skirt slightly pinched mouth. The fat side of the tail is sticky.　Western Pacific Rock Oyster Neutral oyster flavor, sweet meat, light seawater flavor.　Seattle Rock Oyster Clean flavor, crisp, not fat. The seawater flavor is light. The aroma of the oyster remains in the mouth after eating.　Eat oysters by month American oysters, Australian oysters : September October November Irish oysters : early December Japanese oysters, French oysters : mid-December Figure: in counterclockwise order: 1, Scottish gold shell stone oysters 38 yuan / 2, Seattle stone oysters 38 yuan / 3, Irish oysters 38 yuan / 4, the United States Taylor stone oysters 50 yuan / 5, the United States treasured the Pacific stone oysters 48 yuan /