...selection has actually converted a swimbladder into a lung, or organ used exclusively for respiration. I can indeed hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating apparatus or swimbladder." — P. 191. Which theory Mr. Darwin considers to account satisfactorily...

...assuming it, what nse will he make of it ? In the next page (191) he carries on the argument thus : — " I can indeed hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating apparatus, or swimbladder. We can thus, as I infer from Pr >fessor Owen's interesting description...

...gradation. Light will be thrown on the origin of man and hw history ." Elsewhere he had already said, " I can, indeed, hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating apparatus or swim-bladder. We can thus . . . understand the strange fact, that every particle...

...the water at the same time that they also breathe free air in their swimbladders. Believe me, sir, all vertebrate animals having true lungs have descended,...by ordinary generation, from an ancient prototype furnished with a swimming-bladder. As successive generations of aquatic animals became first amphibious...

...selection has actually converted a swimbladdei into a lung, or organ used exclusively for respiration. I can, indeed, hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating apparatus or swimbladder. We can thus, as I infer from Professor Owen's interesting description...

...selection has actually converted a swimbladder into a lung, or organ used exclusively for respiration. I can, indeed, hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating apparatus or swimbladder. We can thus, as I infer from Professor Owen's interesting description...

...variations in the straggle for Life." " I need hardly doubt," he says again, " that all vertebrate nnimal?, having true lungs, have descended by ordinary generation...prototype, of which we know nothing, furnished with a floating apparatus, or swim-bladder. We can thus, as I infer from Professor Owen's interesting description...

...exclusively for respiration." On this view it may be inferred that all verteberate animals having two lungs have descended by ordinary generation from an...prototype of which we know nothing, furnished with a floating apparatus or swim-bladder (p. 210), which means in plain English that mammals and man himself...

...for Life." " I need hardly donbt," he says again, "that all vertebrate animals, having trne lnngs, have descended by ordinary generation from an ancient prototype, of which we know nothing, fnrnished with a floating apparatns, or swim-bladder. We can thns, as I infer from Professor Owen's...

...that the theory of descent with modification embraces all the members of the same class."" And again: "I can indeed hardly doubt that all vertebrate animals...prototype, of which we know nothing, furnished with a floating . . . ; whilst his is not supported by any evidence that rotalinea or nummulites ever originate...