Corrosion, enlightened, and histologic preparations were used to study the macro and microvascularization of the papilla in sheep. It was found that blood is supplied by 2 arteries and 4 to 6 papillary veins with thickened walls and numerous valves along their length. At the base of the papilla there forms a weaker arterial and a stronger venous ring with well defined sinusoid dilatations. There is a vascular muscular layer within the wall of the papilla in which the smooth muscle fibres are oriented in three directions: lengthwise, oblique, and circular; these, however, do not form definitely distinguishable layers. There are in the mucous membrane of the cistern 2 clearly distinguishable vascular nets, each of which is represented by vessels of varying size and direction. At the transition between the cistern and the papillary canal a dense vascular plexus is formed consisting of cross venous anastomoses with which this site assumes the appearance of a cavernous body. The mucous membrane of the papillary canal has shown vascularization that is similar to that of the skin of the papilla. The lengthwise disposition of the big vessels deeply in close proximity to the mucous membrane of the cistern and the papillary canal is of definite practical interest to the surgery of the papillary wall.