What is "hemipenis"

n. (context zoology English) Each of a pair of intromittent organs of male snakes and lizards, usually held inverted within the body but everted for reproduction via erectile tissue.

A hemipenis (plural hemipenes) is one of a pair of intromittent organs of male squamates ( snakes, lizards and worm lizards). Hemipenes are usually held inverted within the body, and are everted for reproduction via erectile tissue, much like that in the human penis. They come in a variety of shapes, depending on species, with ornamentation, such as spines or hooks.