cated by the fact that Cuvier, with far better material and more extensive knowledge, was constantly deceived by "adaptive" (or homoplastic) resemblances, and that even Professor Cope, who wrote much on homoplastic and convergent evolution, was himself deceived by the similarities of structure in the Marsupial "mole," Notoryctes, and the Cape Golden mole (Chrysochloris), an undoubted Insectivore. Furthermore, that even the most "inexcusable" blunder of Linnæus, that of placing rhinoceros with the Rodents under the order "Glires," was due, not to carelessness, but to the fact that the Indian rhinoceros has a single pair of close-set cutting incisors in the upper jaw which oppose the elongate incisor-like appressed canines of the lower jaw, and thus show a superficial approach to the Rodent dentition. If Linnæus had known that Hyrax, which Pallas described as a Rodent ("Cavia"), had cheek teeth like those of Rhinoceros, he doubtless might have felicitated himself upon his supposed astuteness.
In brief, Linnæus (as fully shown by Whewell[1]) from his profound and wide botanical knowledge, was acquainted with many natural orders and strove constantly to recognize others; he knew that a character of great diagnostic and fundamental value in one order may be of slight value in another; he knew that even in a natural order some of the diagnostic and fundamental characters might be absent in certain members otherwise clearly allied to a given series. He knew that a natural series is natural because of the totality of its characters, that the "genus makes the character" and not vice versa—a hard doctrine to many of his contemporaries. And when he had arrived at a conception of any given natural order he selected certain characters as diagnostic but not necessarily universal, and constructed professedly artificial or only partially natural keys to his "natural" orders.
Thus we may believe that when Linnæus turned his attention to the classification of animals he followed the same principles. And in this application of the principles gained in one subject to the data of another, we have a good example of the felicitous union of specifically distinct ideas to produce a line of ideas that were new and very fertile.
- ↑ Op. cit., pp. 319-325.
