( ( The ( ductus deferens ) ) ( ( is ( ( another ( muscular tubule ) ) ( that ( ( carries ( sperm downstream ) ) ( from ( the epididymis ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ ductus) (NNS deferens)) (VP (VBZ is) (NP (NP (DT another) (JJ muscular) (NN tubule)) (SBAR (WHNP (WDT that)) (S (VP (VBZ carries) (NP (NN sperm) (NNS downstream)) (PP (IN from) (NP (DT the) (NNS epididymis)))))))) (. .)))
The ductus deferens  is another muscular tubule that carries sperm downstream from the epididymis.
(ROOT (S (NP (DT A) (NN vas) (NNS deferens)) (VP (VBZ is) (NP (NP (DT the) (NN name)) (PP (IN of) (NP (NP (DT the) (NN tube)) (SBAR (WHNP (WDT that)) (S (VP (VBZ carries) (NP (NN sperm)) (PP (IN from) (NP (NP (DT the) (NNS epididymis)) (PP (TO to) (NP (DT the) (NN urethra)))))))))))) (. .)))