A paired accessory, glandular, androgen-dependent outpouchings of the proximal ductus deferens, one on each side, that produce and secrete lipids and glycogen, components of the seminal fluid; they open into the ampullae at the level of the colliculus seminalis, are lined by simple columnar epithelium with large, oval nuclei, and may be distinguished from those of the prostate as they are surrounded by a characteristic, dense, fibromuscular stroma [ ]