United Kingdom

Cabinet Card, Lambert Weston & Son, in Dover and Folkestone

Royal East Kent Mounted Rifles

The East Kent Mounted Rifles were the only Yeomanry Regiment with the Mounted Rifles denomination.
That title was adopted by the East Kent Yeomanry in 1853, when the Regiment was fitted with carbines - though it remained Yeomanry, and is not to be mixed up with Rifle Volunteer units.
The Royal title was granted in April 1856 by Queen Victoria.
In 1873, when the Duke of Connaught was appointed honorary Colonel, the Regiment became  the Royal East kent Mounted Rifles (Duke of Connaught's Own).

This subject is wearing the 1863 uniform, with a distinctive rifle-green jacket, adorned with four rows of curved braiding and with scarlet facings.
The equally distinctive astrakhan busby is topped by a green over scarlet plume.

This subject might well be an officer, as hinted by the pouch belt pattern, and the green under scarlet throat plume worn by his horse.