Which magazine serialized 'At the Mountains of Madness' in 1936?

Which magazine serialized “At the Mountains of Madness” in 1936? Astounding Stories serialized it. H. P. Lovecraft’s Antarctic novella appeared in the February, March, and April 1936 issues.

Lovecraft wrote the story in 1931, but Weird Tales rejected it because of its length. Literary agent Julius Schwartz later submitted it to Astounding Stories editor F. Orlin Tremaine, who accepted it. The serialization brought Lovecraft $315, his largest payment for a story at that time.

The original magazine text was heavily edited: spelling, punctuation, paragraphing, and some passages were changed or cut. Later editions attempted to restore Lovecraft’s intended text. Weird Tales is an easy mix-up because it was Lovecraft’s best-known market and had initially rejected the novella, but it was not the magazine that first published it. The story follows William Dyer’s disastrous Miskatonic University expedition to Antarctica.