QUANTITATIVE HISTOMORPHOLOGY OF THE BLIND MOLE-RAT HARDERIAN-GLAND

Anatomical, histological and morphometric studies have been performed on the harderian gland and its surroundings in the blind mole rat (Spa lax ehrenbergi). The gland is tubuloalveolar with no true duct system. All ducts within the gland are formed by a single epithelial cell typ e and drain into a wide secretory duct. This opens into the conjunctiv al sac which serves as a reservoir for harderian secretions. Drainage from the conjunctival sac follows 2 possible routes: one through the n asolacrimal duct to the external nasal cavity, the other through a uni que excretory duct that emerges from the anteromedial part of the conj unctival sac and runs through the dermis to the skin, opening at the b ase of a hair follicle. The function of this newly described duct is d iscussed. Morphometric studies revealed that the lumen volume fraction in the female, slightly smaller than that of the male during the summ er, becomes significantly greater during the winter breeding season. T he dimorphism and seasonal variations found in the gland acini suggest s that the gland may be implicated in pheromone production.