One more vintage 1931 yarn from Astounding Stories.
The Heads of Apex by George Henry Weiss
"Far under the sea-floor Solino's submarine carries two American soldiers of fortune to startling adventure among the Vampire Heads of Apex."
Weiss wrote under the pen-name Francis Flagg. All on-line sources give his name as George Henry Weiss, but Bleiler says it's actually Henry George Weiss and I'm going to take his word for it. He describes Weiss as "An intelligent writer, whose work was often original, imaginative, and literate, but constrained by pulp considerations. One of the better writers of the genre pulps..."
Weiss was an early admirer of H. P. Lovecraft, and wrote the poem, "To Howard Phillips Lovecraft" (1938), and the essay, "The Genius of Lovecraft" (1937).