In female frogs, oviducts produce eggs by providing a passage from the inside of the frog's body to the outside world. Biology Corner states that similar structures called vestigial oviducts are found in some male frogs, but they no longer provide the same function.
All female vertebrates, except for jawless fish, have oviducts or an equivalent piece of anatomy. The oviducts found in amphibians, such as frogs, are simple tubes lined with glands that produce mucus and jelly. In mammals oviducts are more commonly known as Fallopian tubes. Even though amphibians have slightly different structures, they still provide the same function as in mammals.
The location of the oviducts does vary somewhat between species, though they are always near the ovaries. The University of Virginia found the oviducts in frogs are located along the sides of the body cavity, and they appear as coiled, yellowish tubes. In frogs and other amphibians, the oviducts carry eggs to the cloaca, a posterior opening that serves as the common exit for intestinal, urinary and reproductive tracts. After the oviduct retains fertilized eggs, several frog species give birth to live young because this extended time in the oviduct allows the tadpoles to fully develop. However, the majority of frog species lay fertilized eggs, which hatch later while submerged in water.