_Mess dress uniform._—Blue mess jacket, special full dress trousers, white dress waistcoat with gilt buttons, gold shoulder knots, full dress cap, white shirt and collar, black necktie, black patent leather shoes. The white mess jacket is worn in hot weather and white trousers may be worn with it, in which case the white cap is worn. [Illustration: _Photo by Harris & Ewing, Washington, D. C._ U. S. Marine Corps. Officer, blue undress uniform Field officer of the Line] [Illustration: U. S. Marine Corps. Officers’ headdress 1. Full dress cap, Major General Commandant 2. Full dress cap, field officers 3. Chapeau, Major General Commandant 4. Undress cap, company officers 5. Winter field cap, all officers] The mess jacket is a round shell jacket of dark blue cloth, with standing collar, extending to the points of the hip bones at the sides and curving downward slightly to the front and back. The jacket is worn hooked at the collar but open down the front which has one row of sixteen small Marine Corps gilt buttons. The collar is covered with gold lace braid and the sleeves bear the same ornamentations indicating rank as those worn on the full dress coat. The white mess jacket is of the same style as the blue mess jacket but has no sleeve ornamentation, and is provided with shoulder straps of the same material as the jacket, upon which the insignia of rank are worn in the same manner as on the shoulder straps of the undress coats. The mess dress is worn on occasions when naval officers wear their evening dress uniform. _Summer field uniform._—The summer field uniform is made of khaki colored cotton drill and consists of a coat of the same style and design as the white undress coat, breeches, field hat or khaki-colored cap of the same style as the white cap, tan leather shoes, tan leather strap puttee leggings, and the sword suspended from the tan leather belt and slings, the belt being worn outside of the coat. Mounted officers may wear tan leather boots. The field hat is the wide brimmed brown felt hat worn with the peaked crown, commonly known as the “campaign hat.” It has the Marine Corps device on the front of the crown to indicate the corps, and in the case of officers a hat cord woven of gold and red and finished at the ends with gold and red acorns is worn around the base of the crown. The rank marks worn with the summer field coat are the same as those worn with the white undress, but all corps and staff devices and buttons are of dull finished bronze to make them less conspicuous.