Robert McDonnell

“ Darwin's theory; for the supposition is as unsatisfactory as it is improbable, that such organs are the result of what would seem a whimsical exercise of creative power in framing an organ merely for the sake of symmetry. The total absence, however, of any trace of even an altered or rudimentary organ representing a structure known to exist in certain members of a group, would afford good testimony against the theory of descent ”

“ As the lateral line system exists in the torpedo and other electric fish, in a rather remarkable condition of development, the opinion held by some authors may be set aside, that it in other fishes represents the electric organs; the same may be said for the so-called muciferous system of rays and sharks (which Geoffroy St. Hilaire conceived to represent the torpedo's batteries) , inasmuch as this system also co-exists in the torpedo with the electric organs. ”

“ On the other hand, the candid inquirer must admit, that when in some creatures well-developed special organs exist, while in their immediate kinsfolk (if I may use the term) no trace of kindred structures has been discovered, there herein exists a grave objection to any theory of unity of type resulting from community of descent. ”