The elongated structure connected to the posterior surface of the testis that transports, stores, and matures spermatozoa between testis and vas deferens.
Comment:
[structure-note] "Typically divided into three main regions. In reptiles, there is an additional canal between the testis and the head of the epididymis, which receives the various efferent ducts. This is, however, absent in all birds and mammals. The epididymis is covered by a two layered pseudostratified epithelium. The epithelium is separated by a basement membrane from the connective tissue wall which has smooth muscle cells."; [taxon-note] "A similar, but probably non-homologous, structure is found in cartilaginous fishes" xsd:string {source="WP"}