part of develops from ejaculatory bulb fly_anatomy.ontology Bilaterally symmetric structure with two anterior and two posterior lateral lobes, a sclerotized rod-like apodeme arising from its upper side and muscles fibers radiating from the end of the rod to the side walls. The anterior ejaculatory duct enters the bulb on the upper side and the posterior ejaculatory duct arises between the paired projections on the opposite side. The walls of the bulb consists of a thick columnar epithelium lined with a well developed intima, enclosing a chamber filled with clear viscous fluid. FBbt:00004962 sperm pump ejaculatory duct male-specific anatomical entity multicellular structure presumptive ejaculatory bulb