More on The Beast in the Cave and Alpeus Spring Packard, Jr.

In the production of these cave species, the exceptional phenomena of darkness, want of sufficient food, and unvarying temperature, have been plainly enough _verae causae_. ... while the process of the origination of the new forms which have survived, or been selected by nature, is to be explained by the action of the physical environments of the animals coupled with inheritance-force.

From this point forward, whether it was The Beast in thr Cave, Arthur Jermyn, Dunwich Horror, or Colour Out of Space - or his views of foreigners and races - Lovecraft deeply held onto Neo-Lamarkism.