abnormal Harderian gland pigmentation MP:0003798 MPheno.ontology The Harderian gland does not normally exist in some types of mammals (bats, cows and horses), terrestrial carnivores, and higher primates including human. any anomaly in the coloring of the sebaceous gland located behind the eyeball in the orbit that excretes fluid that facilitates movement of the third eyelid, due to changes in the amount, shape, or distribution of cells producing pigment abnormal Harderian gland morphology abnormal extracutaneous pigmentation