Banca species are as if the Isle of Man had distinct fauna from the rest of the British Isles

An example of an analogy used by a scientist:

"At the eastern extremity of Sumatra, and separated from it by a straight about fifteen miles wide, is the small rocky island of Banca, celebrated for its tin mines…were found several species distinct from those of the adjacent coast of Sumatra. …

There were also two new ground thrushes of the genus Pitta, closely allied to, but quite distinct form, two other species inhabiting both Sumatra and Borneo, and which did not perceptibly differ in thee large and widely separated islands. This is just as if the Isle of Man possessed a peculiar species of thrush and blackbird, distinct from the birds which are common to England and Ireland."

Alfred Russel Wallace

Wallace, A. R. (1869). Malay Archipelago