snails are bisexual. The method of distinguishing female from male of snail is mainly based on the shape of its right antenna. The right antenna of the male snail bends inward to the right (the bent part is the male genitalia). In addition, the female snail is large and round, while the male snail is small and long. Oncomelania hupensis is an oviparous animal, and its reproductive mode is unique. The embryonic development and larval development of Oncomelania hupensis are completed in the mother. It takes about one year for a fertilized egg to produce a baby snail. Oncomelania hupensis lays eggs in batches, and begins to breed from March to April every year. While producing young snails, the female and male parents mate and fertilize, and at the same time, the young snails to be produced in the next year are bred in the mother. A female snail produces about 1 ~ 15 young snails throughout the year. 1, China round snail, shell, conical shape, its height is greater than the height of the shell mouth. Shell tip. The snail layer of the body is enlarged. The surface of shell is smooth without ribs, with obvious growth lines in fine surface, and sometimes folds are formed on the snail layer. The shell surface is yellow-brown or green-brown. The shell mouth is oval, with an acute angle at the top, a black frame at the periphery, a simple outer lip, and the upper part of the inner lip is attached to the body snail wing, partially or completely covering the umbilical hole. Umbilical foramen is slit-shaped. The horniness is a yellowish brown oval thin sheet with obvious concentric growth line, and the horniness is located in the center of the inner lip. 2, the Chinese round snail, the shell is large, oval, and the shell is thin and solid. The shell is 5mm high and 4mm wide. There are 6-7 spiral layers, the surface of each layer is enlarged, the spiral layer grows rapidly in width, and the spiral part is short and wide; The snail layer of the body is particularly enlarged; The top of the shell is sharp and the suture line is deep. The shell surface is green-brown or yellow-brown. The shell mouth is oval, and the periphery often has a black frame edge. The outer lip is simple and the inner lip is thick, covering the umbilical foramen. Umbilical foramen is slit-shaped.