Button, Royal Naval uniform: pattern pre-1901

Fifty-four buttons. Smooth edge. Within a raised circular border on a lined background is a pre-1901 crown with a fouled anchor below.

The twenty-nine black 15 mm buttons and the fifteen 22 mm black horn buttons are petty officer pattern 1879 buttons.
The three white 15 mm buttons and the three white 22 mm buttons are petty officer pattern 1879 buttons.

The remaining four which are not mentioned on the acquisition slip or inventory slip are?
one 18 mm black button. Within a thin raised circular border on a lined background is a pre-1901 crown above a fouled anchor. Petty Officer.
one 22 mm black button. Within a thin raised circular border on a lined background is a pre-1901 crown above a fouled anchor. Petty Officer
one 27 mm black button. Within a raised circular border on a lined background is a pre-1901 crown above a fouled anchor. Petty Officer
one 28 mm black button. On a lined background is a pre-1901 crown above a fouled anchor. Ratings button?

Object Details

ID: UNI5880
Collection: Uniforms
Type: Button
Display location: Not on display
Creator: Cox, T.; James Grove & Sons
Date made: 1879
Credit: National Maritime Museum, Greenwich, London
Measurements: Diameter: 28 mm; Diameter: 27 mm; Diameter: 22 mm; Diameter: 18 mm; Diameter: 15 mm