Today I received this in the mail from my mother, which she found in an antique shop. Despite the water damage, it’s in readable condition.
Carroll Lane Fenton, Darwin as a Naturalist [Little Blue Book No. 567] (Girard, KA: Haldeman-Julius Company, 1924), 64 pages.
Fenton also authored other Little Blue Books about animals, biology, evolution, geology, life of the past, and Ersnt Haeckel. This pdf gives a list of the entire series.