Morphological investagations were carried out on basophilic intranuclear and cytoplasmic inclusion bodies in epithelial cells of the hair bulbs of anagen hair follicles in wild foxes affected with an abnormal hair coat condition. The inclusions, which were DNA-positive, contained numerous minute virus-like particles ("FMVP"). The particles, having a diameter of approximately 13 nm, had an arrangement of capsomer-like subunits of approximately 2-3 nm in diameter and were nonenveloped. The striking resemblance to icosahedral virus was crystallographically and morphologically demonstrated
