(I recently made these scans for a friend of mine, and thought others would enjoy them as well.)
These are Howard V. Brown’s illustrations for H.P. Lovecraft’s classic SF-horror story “The Shadow Out of Time” as it originally appeared in the June 1936 issue of Astounding Science Fiction. Brown also did the cover for this issue. This is one of my favorite stories, by one of my favorite authors.
I’d like to also mention that the tall creature on the right in Illustration #2a is a dead ringer for the squash-like aliens from Murray Leinster’s story “Proxima Centauri” (March 1935), another of my favorite stories. Brown also did the cover for that issue, though Elliott Dold illustrated the interior for that story (apparently after Brown’s cover).
I like to think that one of the exotic beasties collected on the Yithians’ travels included one of those distinctly unfriendly carnivorous vegetables… I can think of fewer creatures more perfectly suited for inclusion in any respectable monster menagerie.