Escape on Venus — Edgar Rice Burroughs

Earth, attempted to help Duare, princess of Vepaja, find her homeland on an unmapped cloud-shrouded planet, they found more trouble than they had ever desired.

They found it in Mypos, the country of the amphibian people; in the land of the Brokols, whose young grow on trees; and in Voo-ad, the city of the human amoebae. How they escape from their startling predicaments is a thrill-a-page novel of Venus by the author of the famous Tarzan tales.