The Galápagos Islands.

The author discusses his expedition to study the Galapagos Islands. He describes his attempts to procure funding for his expedition, his visit to Chatham Island, also known as San Cristobal Island, and the collection of specimens such as gulls and tortoises. He notes the distribution of wildlife across the islands and comments that the islands are continental islands rather than oceanic islands. He theorizes that the islands were once joined together but became separated, allowing the development of different animals on each island. He suggests the study of animals from the islands will reveal how environmental factors influence biological variation more than natural selection.