The book Side by Sides of the World by Charles E. Carder lists two separate James companies.
James & Co; Enos James, gun maker located in Brimingham England, made good quality muzzle loaders and breech loading shotguns, circa 1870 to 1889. Many James guns were imported by several American distributors, including Lamberson, Furman & Co. in 1887 and H & D Folsom in 1889.
James W.H.; English made side by side shotguns, circa 1880's. These were listed in the 1887 catalog of Lamberson, Furman & Co of Chicago. No other history known.