Clasper

A pair of claspers of a shark

noun - A clasper is a male anatomical structure found in sharks that are used in mating. Male sharks have two claspers formed from the posterior portion of their pelvic fin which serve as intromittent organs used to channel semen into the female's cloaca during mating. The clasper is then inserted into the vagina, where it opens like an umbrella to anchor its position. The siphon then begins to contract expelling water and sperm.