The arrangement, number, and anatomy of the facial vibrissa follicles of the southern elephant seal, Mirounga leonina (Linn.), are described. There are three groups of vibrissae: mystacial, supraorbital, and rhinal, containing approximately 38, 7, and 1 follicles, respectively. These specialized hairs appear to be retained for at least 2 yr and are not shed with the pelage hairs at each annual moult. The histology of the vibrissa follicles and associated organs is described and discussed in relation to their sensory function. Vibrissa follicles of elephant seals are different in anatomy from those described in the mouse and rat: the ringwulst is relatively smaller and, in addition to the sebaceous glands, there are tubular glands of unidentified function but resembling apocrine sweat glands.