Definition: Perthiidae is a family of snailfishes, which belong to the order Spondygotrygia and the class Littorinidae. They have a wide range of sizes from small to large, with some species reaching lengths up to 12 inches (30 cm). Perthiidae are known for their distinctive shell patterns that mimic those of certain other marine mollusks, such as the sea snail, and for being able to withstand
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