He thinks it difficult to believe that the wing of a bird "was developed in any other way than by a comparatively sudden modification of a marked and important kind;" and apparently he would extend the same view to the wings of bats and pterodactyles.
Uste du zaila dela sinestea txori baten hegoa "erlatiboki bat-bateko eraldaketa nabarmen eta garrantzitsu bat ez den beste ezein bidez garatu zenik";