The Arcturus 80 (Arcturus called it a 180) is the rectifier. The other 24 is hiding behind it. In the 1920's some manufacturers prefixed the tube number with their "own" identifying number, so a 24 was a 224 when made by RCA, or a 324 if sold by Cunningham. Apparently Arcturus used "1." This practice died out in the 1930's. I always liked those blue tubes and so did the public; they didn't work any better but look so cool, and the box art is out of this world...
http://www.bill01a.com/tubephotos/arct-180.htm