Cornell Collection of Blaschka Invertebrate Models, made in glass.

Boston had…

131 glass models of sea slugs, hydroid jellyfish or craspedotes [made] for the Museum of Natural History Society in Boston in 1880.

… which it’s possible Lovecraft could have seen there, either as a boy or in 1919.

According to the de Camp biography of Lovecraft, he saw their collection of such models at Harvard, and quite early. de Camp, presumably drawing on Sonia’s memory of her courtship of Lovecraft circa Autumn (Fall) 1921, states in the biography that…

Once he [Lovecraft] showed her [Sonia] the display of glass flowers in the Museum of Comparative Zoology at Harvard