There are four classes of officers in the United States navy, and each has its own distinguishing mark. The commissioned officers of the line. The commissioned corps. The warrant officers. The petty officers. The first two classes are graduates of Annapolis, or regularly commissioned by the Government. The last two are composed of enlisted men who have been promoted. The rank device of the commissioned officers is worn on the shoulder-knot of the full dress uniform and on the collar of the service coat. The marks are as follows: [Illustration: REAR-ADMIRAL.] Foul anchor with silver stars at ends; and one stripe of gold lace two inches wide, and one of one-half inch wide above it, on sleeves. [Illustration: COMMODORE.] A star with a foul anchor at either side of it; and one stripe of gold lace two inches wide on sleeves. [Illustration: CAPTAIN.] A spread eagle with foul anchor at either side. Four one-half-inch stripes of gold lace on sleeves. [Illustration: COMMANDER.] Foul anchor with silver oak leaves at ends. Three stripes of half-inch gold lace on sleeves. LIEUTENANT-COMMANDER.--A silver foul anchor with a silver oak leaf at either end. Two stripes of half-inch gold lace with a quarter-inch stripe between. [Illustration: LIEUTENANT.] Silver foul anchor with two silver bars at either side. Two stripes of gold lace one-half inch wide on sleeves. [Illustration: LIEUTENANT--JUNIOR GRADE.] Silver foul anchor with one silver bar at either side. Two stripes of gold lace, half and quarter-inch, on sleeves. [Illustration: ENSIGN.] A gold foul anchor on collar or shoulder-knot and one stripe of gold lace on sleeves. THE COMMISSIONED CORPS. The commissioned corps' devices are substituted for the anchor by staff officers, who wear the same rank devices as are prescribed for line officers with whom they have relative rank. THE PAY CORPS.--A silver oak sprig and a narrow band of white cloth above and below the gold lace on sleeves. THE MEDICAL CORPS.--A spread oak leaf of gold with an acorn of silver, and a band of dark maroon velvet above and below the gold lace on sleeves. THE ENGINEER CORPS.--Four silver oak leaves, and a band of red cloth above and below the gold lace on sleeves. PETTY OFFICERS' RATING MARKS. All petty officers wear a rating device on the sleeve of the outer garment above the elbow. If they belong to the starboard watch the mark will be sewed on the right sleeve; if the port, on the left. [Illustration: QUARTERMASTER.] The petty officers' device always has a spread eagle above it. The specialty mark indicating to which department he belongs is just below in the angle formed by the chevrons. The chevrons indicate the class. Three chevrons, first class; two, second class, and so on. The chief petty officers have an arch of the same cloth connecting the two ends of the top chevron. The specialty marks are as follows: [Illustration: MASTER-AT-ARMS.] [Illustration: GUNNER'S MATES.]