Final answer:
The end of the ductus deferens forms the ampulla, which empties into the ejaculatory duct leading to the prostatic urethra.
Step-by-step explanation:
The terminus of the ductus deferens enlarges to form the region called the (1) Ampulla, which empties into the (2) Ejaculatory duct that is connected to the prostatic urethra. The ampulla acts as a storage and maturation area for sperm before they enter the ejaculatory duct. The ejaculatory ducts are significant as they combine the sperm from the vas deferens with the secretions from the seminal vesicles, and pass this mixture into the prostatic urethra during ejaculation. This sequence contributes to semen formation, which is important for male fertility.