changes and other physiological data supply, is the only sure basis of classification." He was quite aware of the taxonomic value of the vocal organs of some groups of Birds, presently to be especially mentioned, and he had himself ascertained the presence and absence of cæca in a not inconsiderable number of groups, drawing thence very justifiable inferences. He knew at least the earlier investigations of L'Herminier, and, though the work of Nitzsch, even if he had ever heard of it, must (through ignorance of the language in which it was written) have been to him a sealed book, he had followed out and extended the hints already given by Temminck as to the differences which various groups of Birds display in their moult. With all this it is not surprising to find, though the fact has been generally overlooked, that Blyth's proposed arrangement in many points anticipated conclusions that were subsequently reached, and were then regarded as fresh discoveries. It is proper to add that at this time the greater part of his work was carried on in conjunction with Mr. Bartlett, the present Superintendent of the Zoological Society's Gardens, and that, without his assistance, Blyth's opportunities, slender as they were compared with those which others have enjoyed, must have been still smaller. Considering the extent of their materials, which was limited to the bodies of such animals as they could obtain from dealers and the several menageries that then existed in or near London, the progress made in what has since proved to be the right direction is very wonderful. It is obvious that both these investigators had the genius for recognizing and interpreting the value of characters; but their labours do not seem to have met with much encouragement; and a general arrangement of the Class laid by Blyth before the Zoological Society at this time 1 does not appear in its publications, possibly through his neglect to reduce his scheme to writing and deliver it within the prescribed period. But even if this were not the case, no one need be surprised at the result. The scheme could hardly fail to be a crude performance—a fact which nobody would know better than its author; but it must have presented much that was objectionable to the opinions then generally prevalent. Its line to some extent may be partly made out very clearly, for the matter of that, so far as its details have been published in the series of papers to which reference has been given—and some traces of its features are probably preserved in his Catalogue of the specimens of Birds in the Museum of the Asiatic Society of Bengal, which, after several years of severe labour, made its appearance at Calcutta in 1849; but, from the time of his arrival in India, the onerous duties imposed upon Blyth, together with the want of sufficient books of reference, seem to have hindered him from seriously continuing his former researches, which, interrupted as they were, and born out of due time, had no appreciable effect on the views of systematizers generally.

Next must be noticed a series of short treatises communicated by Johann Friedrich Brandt, between the years 1836 and 1839, to the Academy of Sciences of St. Petersburg, and published in its Mémoires.

1 An abstract is contained in the Minute-book of the Scientific Meetings of the Zoological Society, 26th June and 10th July 1838. The Class was to contain fifteen Orders, but only three were dealt with in any detail.

f

In the year last mentioned the greater part of these was separately issued under the title of Beiträge zur Kenntniss der Naturgeschichte der Vögel. Herein the author first assigned anatomical reasons for rearranging the Order Anseres of Linnæus, the Natatores of Illiger, who, so long before as 1811, had proposed a new distribution of it into six Families, the definitions of which, as was his wont, he had drawn from external characters only. Brandt now retained very nearly the same arrangement as his predecessor; but, notwithstanding that he could trust to the firmer foundation of internal framework, he took at least two retrograde steps. First he failed to see the great structural difference between the Penguins (which Illiger had placed as a group, Impennes, of equal rank to his other Families) and the Auks, Divers and Grebes, Pygopodes-combining all of them to form a "Typus" (to use his term) Urinatores; and secondly he admitted among the Natatores, though as a distinct "Typus" Podoidæ, the genera Podoa (FINFOOT), and Fulica (CooT), which are now known to be allied to the Rallidæ. At the same time he corrected the error made by Illiger in associating the PHALAROPES with these forms, rightly declaring their relationship to Tringa, a point of order which other systematists were long in admitting. On the whole Brandt's labours were of no small service in asserting the principle that consideration must be paid to osteology; for owing to his position he was able to gain more attention to his views than some of his less favourably placed brethren had succeeded in doing.

In the same year (1839) another slight advance was made in the classification of the true Passeres. Keyserling and Blasius briefly pointed out (Arch. f. Naturgesch. v. pp. 332-334) that, while all the other Birds provided with perfect song-muscles had the "planta" or hind part of the "tarsus" covered with two long and undivided horny plates, the Larks had this part divided by many transverse sutures, so as to be scutellated behind as well as in front; just as is the case in many of the Passerines which have not the singing-apparatus, and also in the HOOPOE. The importance of this singular but superficial departure from the normal structure has been so needlessly exaggerated as a character that at the present time its value is apt to be unduly depreciated. In so large and so homogeneous a group as that of the true Passeres, a constant character of this kind is not to be despised as a practical mode of separating the Birds which possess it; and, more than this, it would appear that the discovery thus announced was the immediate means of leading to a series of investigations of a much more important and lasting nature—those of Johannes Müller to be presently mentioned.

Again we must recur to that indefatigable and most original investigator Nitzsch, who, having never intermitted his study of the particular subject of his first contribution to science, in 1833 brought out at Halle, where he was Professor of Zoology, an essay with the title Pterylographiæ Avium Pars prior. It seems that this was issued as much with the object of inviting assistance from others in view of future labours, since the materials at his disposal were scanty, as with that of making known the results to which his researches had already led him. Indeed he only communicated copies of this essay to a few friends, and

examples of it are comparatively scarce. Moreover, he stated subsequently that he thereby hoped to excite other naturalists to share with him the investigations he was making on a subject which had hitherto escaped notice or had been wholly neglected, since he considered that he had proved the disposition of the feathered tracts in the plumage of Birds to be the means of furnishing characters for the discrimination of the various natural groups as significant and important as they were new and unexpected. There was no need for us here to quote this essay in its chronological place, since it dealt only with the generalities of the subject, and did not enter upon any systematic details. These the author reserved for a second treatise which he was destined never to complete. He kept on diligently collecting materials, and as he did so was constrained to modify some of the statements he had published. He consequently fell into a state of doubt, and before he could make up his mind on some questions which he deemed important he was overtaken by death.2 Then his papers were handed over to his friend and successor, Burmeister, afterwards and for many years of Buenos Aires, who, with much skill elaborated from them the excellent work known as Nitzsch's Pterylographie, which was published at Halle in 1840. There can be no doubt that the editor's duty was discharged with the most conscientious scrupulosity ; but, from what has been just said, it is certain that there were important points on which Nitzsch was as yet undecided—some of them perhaps of which no trace appeared in his manuscripts, and therefore as in every case of works posthumously published, unless (as rarely happens) they have received their author's "imprimatur," they cannot be implicitly trusted as the expression of his final views. It would consequently be unsafe to ascribe positively all that appears in this volume to the result of Nitzsch's mature consideration. Moreover, as Burmeister states in his preface, Nitzsch by no means regarded the natural sequence of groups

1 It is still a prevalent belief that feathers grow almost uniformly over the whole surface of a Bird's body; some indeed are longer and some are shorter, but that is about all the difference perceptible to most people. It is the easiest thing for anybody to satisfy himself that this, except in a few cases, is altogether an erroneous supposition (see PTERYLOSIS). Before Nitzsch's time the only men who seem to have noticed this fact were the great John Hunter and the accurate Macartney. But the observations of the former on the subject were not given to the world until 1836, when Owen introduced them into his Catalogue of the Museum of the College of Surgeons in London (vol. iii. pt. ii. p. 311), and therein is no indication of the fact having a taxonomical bearing. The same may be said of Macartney's remarks, which, though subsequent in point of time, were published earlier, namely, in 1819 (Rees's Cyclopædia, xiv. art. 'Feathers '). Ignorance of this simple fact has led astray many celebrated painters, among them Landseer, whose pictures of Birds nearly always shew an unnatural representation of the plumage that at once betrays itself to the trained eye, though of course it is not perceived by spectators generally, who regard only the correctness of attitude and force of expression, which in that artist's work commonly leave little to be desired. Every draughtsman of Birds to be successful should study as did Mr. Wolf, the plan on which their feathers are disposed.

2 Though not relating exactly to our present theme, it would be improper to dismiss Nitzsch's name without reference to his extraordinary labours in investigating the insect and other external parasites of Birds, a subject which as regards British species was subsequently elaborated by Denny in his Monographia Anoplurorum Britannia (1842) and in his list of the specimens of British Anoplura in the collection of the British Museum.

as the highest problem of the systematist, but rather their correct limitation. Again the arrangement followed in the Pterylographie was of course based on pterylographical considerations, and we have its author's own word for it that he was persuaded that the limitation of natural groups could only be attained by the most assiduous research into the species of which they are composed from every point of view. The combination of these three facts will of itself explain some defects, or even retrogressions, observable in Nitzsch's later systematic work when compared with that which he had formerly done. On the other hand some manifest improvements are introduced, and the abundance of details into which he enters in his Pterylographie renders it far more instructive and valuable than the older performance. As an abstract of that has already been given, it may be sufficient here to point out the chief changes made in his newer arrangement. To begin with, the three great sections of Aerial, Terrestrial and Aquatic Birds are abolished. The "Accipitres are divided into two groups, Diurnal and Nocturnal; but the first of these divisions is separated into three sections :-(1) the Vultures of the New World, (2) those of the Old World and (3) the genus Falco of Linnæus. The " 'Passerinæ," that is to say, the true Passeres, are split into eight Families, not wholly with judgment; but of their taxonomy more is to be said presently. Then a new Order "Picaria" is instituted for the reception of the Macrochires, Cuculinæ, Picinæ, Psittacinæ and Amphibolæ of his old arrangement, to which are added three 2 others Caprimulginæ, Todide and Lipoglossæ-the last consisting of the genera Buceros, Upupa and Alcedo. The association of Alcedo with the other two is no doubt a misplacement, but the alliance of Buceros to Upupa, already suggested by Gould and Blyth in 18383 (Mag. Nat. Hist. ser. 2, ii. pp. 422 and 589), though at first sight unnatural, has been corroborated by many later systematizers; and taken as a whole the establishment of the Picaria was certainly a commendable proceeding. For the rest there is only one considerable change, and that forms the greatest blot on the whole scheme. Instead of the Ratitæ of Merrem being recognized as before as a Subclass, they were now reduced to the rank of an Order under the name "Platysternæ," and placed between the "Gallinacea" and "Gralla," though it was admitted that in their pterylosis they differ from all other Birds, in ways that the author is at great pains

1 A short essay by Nitzsch on the general structure of the Passerines, written, it is said, in 1836, was published in 1862 (Zeitschr. Ges. Naturwissensch. xix. pp. 389408). It is probably to this essay that Burmeister refers in the Pterylographie (p. 102, note; English translation, p. 72, note) as forming the basis of the article "Passerinæ which he contributed to Ersch and Gruber's Encyklopädie (sect. iii. bd. xiii. pp. 139-144), and published before the Pterylographie.

2 By the numbers prefixed it would look as if there should be four new members of this Order; but that seems to be due rather to a slip of the pen or to a printer's

error.

3 This association is one of the most remarkable in the whole series of Blyth's remarkable papers on classification in the volume cited above. He states that Gould suspected the alliance of these two forms "from external structure and habits alone; otherwise one might suppose that he had obtained an intimation to that effect on one of his Continental journeys. Blyth "arrived at the same conclusion, however, by a different train of investigation," and this is beyond doubt.

to describe, in each of the four genera examined by him-Struthio, Rhea, Dromæus and Casuarius.1 It is significant that notwithstanding this he did not figure the pterylosis of any one of them, and the thought suggests itself that, though his editor assures us he had convinced himself that the group must be here shoved in (eingeschoben), the intrusion is rather due to the necessity which Nitzsch, in common with most men of his time (the Quinarians excepted), felt for deploying the whole series of Birds into line, in which case the proceeding may be defensible on the score of convenience. The extraordinary merits of this book, and the admirable fidelity to his principles which Burmeister shewed in the difficult task of editing it, were unfortunately overlooked for many years, and perhaps are not sufficiently recognized now. Even in Germany, the author's own country, there were few to notice seriously what is certainly one of the most remarkable works ever published on the science, much less to pursue the investigations that had been so laboriously begun.2 Andreas Wagner, in his report on the progress of Ornithology (Arch. f. Naturgesch. vii. 2, pp. 60, 61), as might be expected from such a man as he was, placed the Pterylographie at the summit of those publications the appearance of which he had to record for the years 1839 and 1840, stating that for "Systematik" it was of the greatest importance. On the other hand Oken (Isis, 1842, pp. 391-394), though giving a summary of Nitzsch's results and classification, was more sparing of his praise, and prefaced his remarks by asserting that he could not refrain from laughter when he looked at the plates in Nitzsch's work, since they reminded him of the plucked fowls in a poulterer's shop-it might as well be urged as an objection to the plates in many an anatomical book that they called to mind a butcher's-and goes on to say that, as the author always had the luck to engage in researches of which nobody thought, so had he the luck to print them where nobody sought them. In Sweden Sundevall, without accepting Nitzsch's views, accorded them a far more appreciative greeting in his annual reports for 1840-42 (i. pp. 152-160); but of course in England and France 3 nothing was known of them beyond the scantiest notice, generally taken at second hand, in two or three publications.4

1 He does not mention Apteryx, at that time so little known on the Continent. 2 Some excuse is to be made for this neglect. Nitzsch had of course exhausted all the forms of Birds commonly to be obtained, and specimens of the less common forms were too valuable from the curator's or collector's point of view to be subjected to a treatment that might end in their destruction. Yet it is said, on good authority, that Nitzsch had the patience so to manipulate the skins of many rare species that he was able to ascertain the characters of their pterylosis by the inspection of their inside only, without in any way damaging them for the ordinary purpose of a museum. Nor is this surprising when we consider the marvellous skill of Continental and especially German taxidermists, many of whom have elevated their profession to a height of art inconceivable to most Englishmen, who are only acquainted with the miserable mockery of Nature which is the most sublime result of all but a few "birdstuffers."

3 In 1836 Jacquemin communicated to the French Academy (Comptes Rendus, ii. pp. 374, 375 and 472) some observations on the order in which feathers are disposed on the body of Birds; but, however general may have been the scope of his investigations, the portion of them published refers only to the Crow, and there is no mention made of Nitzsch's former work.

4 Thanks to Mr. Sclater, the Ray Society was induced to publish, in 1867, an