One generation removed from Mr. Lincoln’s Corps
Marine Lt. Wendell Cushing Neville (far left, with sword) presents the Marine Guard detachment aboard the 2nd-class battleship/armored cruiser USS Maine (ACR-1), circa 1895. Note the Springfield M1884 “Trapdoor” single-shot .45-70 rifles with the same musket-style bayonet that Napoleon would recognize, kepi headgear, leather M1864 knapsacks and “U.S.M.C” marked haversacks.
All in all, not too different from the same Marine Corps that walked the decks for Dahlgren, Farragut, and Porter.

Note the ages of these regulars. You can bet they were rather salty. From the Wendell C. Neville Collection (COLL/2985) in the Marine Corps Archives & Special Collections.
Neville (USNA 1890), of note, would later receive a MOH for his work in Mexico, lead the much better-equipped 5th Marines at Belleau Wood, and become the 14th Commandant of the Marine Corps in 1929.
Maine would later be sunk in Havana Harbor in 1898, sparking the Spanish-American War.