THE POSSIBILITY of studying the blood vessels of both the spiral ligament and stria vascularis of living guinea pigs occurred to one of us (F. L. W.). The purposes of this article are to describe the exposure of the spiral ligament and stria vascularis in living anesthetized guinea pigs and to present a series of microscopic observations on the small blood vessels of this area. During the past century both histologists and otologists have been intensely interested in the circulation of the inner ear. Using an array of various histological techniques, many investigators have attempted to define with accuracy the small blood vessels of the spiral ligament and stria vascularis (for instance, Huschke,1 Retzius,2 Voltolini,3 Bœttcher,4 Schwalbe,5 Siebenmann,6 Shambaugh,7 Nabeya,8 Belemer,9 Agazzi,10 and Smith11). Certain basic differences of opinion have arisen involving the morphology and physiology of these vessels.