An order of ray-finned fish, also called the Microcyprini, and comprising mostly small, fresh-water fish. They are closely related to the Atheriniformes[?] and are occasionally included with them. Many popular aquarium fish, such as killifish and live-bearers, belong here.
... opens at the end of the penis.
Medical problems of the urethra:
Hypospadias[?] is a form of abnormal development of the urethra in the male, where the opening is ...