See de Ricci, English book collectors, pp. 86, 171-2, 178
As he acquired manuscripts, Perrins applied his bookplate to the upper pastedown, and a circular numbered label to the upper left corner of the lower pastedown. When the collection came to be catalogued they were re-numbered according to country of origin, and these numbers are fund on a different circular label in the top right corner of the upper pastedown, and at teh base of the spine
He occasionally (but rarely) used a green leather bookplate (here in black and white):
