In 1841, Robert Merry's Museum included a few hand-colored plates picturing various animals; they made natural history more interesting, subscriber Emily C. Crafts assured "Uncle Robert Merry" in 1843. (She also complained that "when they bound my numbers, they kept all my painted pictures, and did not put them into the volume which they bound. This grieves me much, and I thought I would tell it to you.") Remembering the plates decades later, William Oliver Stevens was uncomplimentary, but grateful: "I remember one frontispiece of a hyena. He had a smear of lavender all over himself and the sky behind, and the grass he stood on boasted three poisonous shades of green. It looks horrible now, but in those days it was wonderful."
The illustrations have no apparent connection with pieces in the issues, and probably weren't created for the Museum. They were likely included because Samuel Goodrich believed in the educational power of illustrations: "Before I began to talk of a lion, I gave a picture of a lion--my object being ... to have the child start with a distinct image of what I was about to give an account of. Thus I secured his interest in the subject, and thus I was able to lead his understanding forward in the path of knowledge." (Recollections of a Lifetime, vol 2, p. 311)
The illustrations also were, like almost all illustrations of the time, recycled, with the Newfoundland appearing in The Youth's Companion 14 years later. Small versions of the hyena were printed in several books and periodicals in the nineteenth century.
Here are the four hand-colored illustrations I know were in the 1841 volume. They may have been included more randomly than it appears: the crocodile is with the April issue in one volume I have, and with the August issue in another bound volume made up of randomly selected issues. The December 1841 issue also had a natural history plate: one of a squirrel which was not colored.