See Letter 120.) has been well laughed at, and disingenuously distorted by some into my saying that a bear could be converted into a whale.

As it offended persons, I struck it out in the second edition; but I still maintain that there is no especial difficulty in a bear's mouth being enlarged to any degree useful to its changing habits,--no more difficulty than man has found in increasing the crop of the pigeon, by continued selection, until it is literally as big as the whole rest of the body.

If this had not been known, how absurd it would have appeared to say that the crop of a bird might be increased till it became like a balloon! With respect to the ostrich, I believe that the wings have been reduced, and are not in course of development, because the whole structure of a bird is essentially formed for flight; and the ostrich is essentially a bird.

You will see at page 182 of the "Origin" a somewhat analogous discussion.

At page 450 of the second edition I have pointed out the essential distinction between a nascent and rudimentary organ.