Inhabitants of the Nameless City and Yoth

Hollow Earth Fauna: creatures from The Nameless City (1921) by H.P. Lovecraft

The Nameless City - The Nameless City of the story's title is an ancient ruin located somewhere in the deserts of the Arabian Peninsula and is older than any human civilization.

In ancient times, the Nameless City was built and inhabited by an unnamed race of reptiles with a body shaped like a cross between a crocodile and a seal with a strange head common to neither, involving a protruding forehead, horns, lack of a nose and an alligator-like jaw. These beings moved by crawling; thus, the architecture of the city has very low ceilings and some places are too low for a human being to stand upright. Their city was originally coastal, but when the seas receded it was left in the depths of a desert. This resulted in the decline and eventual ruin of the city, while the inhabitants fled underground to a white-lit place where they survived to the modern day.

Abdul Alhazred spent time in the city.

"To convey any idea of these monstrosities is impossible. They were of the reptile kind, with body lines suggesting sometimes the crocodile, sometimes the seal, but more often nothing of which either the naturalist or the palaeontologist ever heard. In size they approximated a small man, and their fore legs bore delicate and evidently flexible feet curiously like human hands and fingers. But strangest of all were their heads, which presented a contour violating all known biological principles. To nothing can such things be well compared—in one flash I thought of comparisons as varied as the cat, the bulldog, the mythic Satyr, and the human being. Not Jove himself had so colossal and protuberant a forehead, yet the horns and the noselessness and the alligator-like jaw placed the things outside all established categories. I debated for a time on the reality of the mummies, half suspecting they were artificial idols; but soon decided they were indeed some palaeogean species which had lived when the nameless city was alive. To crown their grotesqueness, most of them were gorgeously enrobed in the costliest of fabrics, and lavishly laden with ornaments of gold, jewels, and unknown shining metals."


They were also mentioned in Lovecraft's The Mound as having lived in a place called Yoth, a red-lit cavern beneath K'n-yan (which is itself located beneath Oklahoma). 

"the reptilian quadrupeds of Yoth"