THE LAW OF THE WILD (Mascot, 1934), 12 chapters, was directed by Armand Schaefer and B. Reeves "Breezy" Eason.

Bob Custer (1897 or 98 - 1974) was a cowboy hero in silents, but he never made it big in talkies.  His real name was Raymond Anthony Glenn and he could not adapt to the dialog required in talkies --- to be blunt, he was terrible delivering any lines.  The dozen or so sound westerns he made were for the lower echelon production outfits, and around 1937, Custer left the business.

At Nat Levine's Mascot cliffhanger factory, Rex (the black hoss) and Rin-Tin-Tin Jr. (the dog) got top billing, probably because they had more drawing power than Custer.  In the top lobby card, Custer is persuading Edmund Cobb, and in the bottom lobby, he's pounding perpetual baddie Dick Cramer.