👉 Gyranusoidea is a class of marine invertebrates that includes a group of animals known for their unique reproductive strategies, such as the development of male and female reproductive organs. These organisms are characterized by a single, complex organ called a gyra (a type of gill), which acts like a penis or a scrotum. This organ is often used to facilitate fertilization, although it also plays an important role in maintaining buoyancy and regulating body temperature.