How do you tell first edition book Tarzan Of The Apes?

The American first edition of "Tarzan of the Apes" will have "A.C. McClurg" written on the spine and title page. Other reprints will have "A.L. Burt" or "Grosset & Dunlap" written on the spine and title page. There are 3 different states of the first edition for this title. The website, erbfirsts.com has photos and more information on this and all other Edgar Rice Burroughs first edition books.