in animals, a duct through which the coelom communicates with the external environment. Coelomoducts develop from the embryo’s mesoderm. Their primary function is the removal of sexual waste products.

In the course of evolution, for example, in polychaete worms, the coelomoducts also acquired the excretory function. In vertebrates, groups of typical coelomoducts form the kidneys. Coelomoducts usually open into the coelom through ciliated infundibular passages.