This mechanism is similar to the formation of cirrus uncinus clouds. The name "cirrus uncinus" is derived from Latin, meaning "curly hooks". The species "uncinus" is similar but has upturned hooks at the ends. Cirrus uncinus is a type of cirrus cloud. Overall, they were fish-hook shaped, and probably only the uncinus was exposed. "Cirrus uncinus" clouds are hooked and are the form that is usually called "mare's tails".