During a recent study of human fetal scalp hair follicle morphogenesis we observed, unexpectedly, a well-defined appendageal bud growing from the ental surface of stage 3 follicles. This appendage extends out and down from the follicle peg at the distal-most intra-dermal portion, close to, but separate from, the epidermis. By conventional histology this small appendage is only variably observed; however, by scanning electron microscopy the bud is present on every stage 3 follicle studied. Shortly after stage 3 the bud disappears; we have never found it on stage 5 follicles. Scanning electron microscopic images of newborn opossum skin show definitive apocrine glands arising form the same site as the human stage 3 bud, though, in this case, the structure does not regress. The cells making up this appendage specifically express Activin B, a putative marker of apocrine precursor cells; they also stain strongly for K19, K15 and CD200. This observation suggests that all human scalp hair follicles form an apocrine gland anlage which then rapidly regresses - a possibility suggested, but not well-demonstrated, in the old literature. This formation-loss process appears to be another example of atavistic organs, such as the tooth progenitor of the fetal whale, and the eye of the blind cave fish embryo, both of which regress with development. The rare metaplastic presence of apocrine glands in human hair follicles after birth may result from an abnormal block in the regression process.