So again it is probable, from what we know of the embryos of mammals, birds, fishes, and reptiles, that these animals are the modified descendants of some ancient progenitor, which was furnished in its adult state with Branchiae, a swim-bladder, four fin-like limbs, and a long tail, all fitted for an aquatic life.
"Darwin and Modern Science"
A.C. Seward and Others
Why none of us started specialising Branchiae I do not know, but feel that would have been the proper sort of breathing apparatus for such an atmosphere.
"West African studies"
Mary Henrietta Kingsley