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an excretory tubule of the mesonephros.
Synonym(s): segmental tubule
any of the embryonic renal tubules composing the mesonephros. They function as excretory structures during the early embryonic development of humans and other mammals but are later incorporated into the reproductive system. In males the tubules give rise to the efferent and aberrant ductules of the testes, the appendix epididymis, and the paradidymis; in females, to the epoöphoron, paroöphoron, and vesicular appendices. All of the structures are vestigial except the efferent ductules of the testes.
One of the embryonic tubules that in the female gives rise only to vestigial structures but in the male gives rise to the efferent ducts of the testes.
See also: tubule