Iris sphincter muscle Iris sphincter muscle The iris sphincter muscle (pupillary sphincter, pupillary constrictor, circular muscle of iris, circular fibers) is a muscle in the part of the eye called the iris. It encircles the pupil of the iris, appropriate to its function as a constrictor of the pupil. It is found in vertebrates and some cephalopods. Initially, all the myocytes are of the smooth muscle type but, later in life, most cells are of the striated muscle type. Its dimensions are about 0.75 mm wide by 0.15 mm thick. In humans, it functions to constrict the pupil in bright light (pupillary light
World Colored Light Heavyweight Championship met reigning colored heavyweight champ Harry Wills on 2 March 1922 in Madison Square Garden in New York City for a 15-round bout, losing to the great champion via a K.O. in the second round. Wills outweighed him by 25¾ lbs. On May 9 of that year, Lee Anderson took on Tiger Flowers in Ciudad Juarez, Mexico for a 15-round bout to determine the colored light heavyweight title. Anderson won his second colored crown when he K.O.-ed Flowers in the seventh round. Anderson apparently vacated the title in turn, and Kid Norfolk took the crown title for the second time