The final accessory glands to add fluid to semen, sometimes called Cowper's glands, are the:

1. Semen receives contributions from three accessory glands in sequence: seminal vesicles, prostate, then a final gland. 2. This final gland releases a thick, salty lubricating fluid, sometimes called pre-ejaculate. 3. This pair of glands is called the bulbourethral glands, also known as Cowper's glands. 4. So bulbourethral glands is correct. _Source: OpenStax Anatomy and Physiology (CC BY 4.0), Ch 27 "The Reproductive System", p.1287 §Bulbourethral Glands_