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Rh find favour with his scientific superiors, and for the time things remained as though his investigations had never been carried on.

Two years later Nitzsch, who was indefatigable in his endeavour to discover the natural families of birds and had been pursuing a series of researches into their vascular system, published the result, at Halle in Saxony, in his Observationes de avium arteria carotide communi, in which is included a classification drawn up in accordance with the

variation of structure which that important vessel presented in the several groups that he had opportunities of examining. By this time he had visited several of the principal museums on the Continent, among others Leyden (where Temminck resided) and Paris (where he had frequent intercourse with Cuvier), thus becoming acquainted with a considerable number of exotic forms that had hitherto been inaccessible to him. Consequently his labours had attained to a certain degree of completeness in this direction, and it may therefore be expedient here to name the different groups which he thus thought himself entitled to consider established. They are as follows:—

I. [L’H. “Oiseaux normaux”].

A. Aves Carinatae aereae. 1. Accipitrinae [L’H. 1, 2 partim, 3]; 2. Passerinae [L’H. 18]; 3. Macrochires [L’H. 6, 7]; 4. Cuculinae [L’H. 8, 9, 10 (qu. 11, 12?)]; 5. Picinae [L’H. 15, 16]; 6. Psittacinae [L’H. 5]; 7. Lipoglossae [L’H. 13, 14, 17]; 8. Amphibolae [L’H. 4]. B. Aves Carinatae terrestres. 1. Columbinae [L’H. 19]; 2. Gallinaceae [L’H. 20]. C. Aves Carinatae aquaticae.

Grallae. 1. Alectorides (＝Dicholophus+Otis) [L’H. 2 partim, 26 partim]; 2. Gruinae [L’H. 23]; 3. Fulicariae [L’H. 22]; 4. Herodiae [L’H. 24 partim]; 5. Pelargi [L’H. 24 partim, 25]; 6. Odontoglossi (＝Phoenicopterus) [L’H. 26 partim]; 7. Limicolae [L’H. 26 paene omnes].

Palmatae. 8. Longipennes [L’H. 27]; 9. Nasutae [L’H. 28]; 10. Unguirostres [L’H. 30]; 11. Steganopodes [L’H. 29]; 12. Pygopodes [L’H. 31, 32, 33, 34]. II. [L’H. “Oiseaux anomaux”].

To enable the reader to compare the several groups of Nitzsch with the families of L’Herminier, the numbers applied by the latter to his families are suffixed in square brackets to the names of the former; and, disregarding the order of sequence, which is here immaterial, the essential correspondence of the two systems is worthy of all attention, for it obviously means that these two investigators, starting from different points, must have been on the right track, when they so often coincided as to the limits of what they considered to be, and what we are now almost justified in calling, natural groups. But it must be observed that the classification of Nitzsch, just given, rests much more on characters furnished by the general structure than on those furnished by the carotid artery only. Among all the species (188, he tells us, in number) of which he examined specimens, he found only four variations in the structure of that vessel, namely:—

1. That in which both a right carotid artery and a left are present. This is the most usual fashion among the various groups of birds, including all the “aerial” forms excepting Passerinae, Macrochires and Picinae.

2. That in which there is but a single carotid artery, springing from both right and left trunk, but the branches soon coalescing, to take a midway course, and again dividing near the head. This form Nitzsch was only able to find in the bittern (Ardea stellaris).

3. That in which the right carotid artery alone is present, of which, according to our author’s experience, the flamingo (Phoenicopterus) was the sole example.

4. That in which the left carotid artery alone exists, as found in all other birds examined by Nitzsch, and therefore as regards species and individuals much the most common—since into this category come the countless thousands of the passerine birds—a group which outnumbers all the rest put together.

Considering the enormous stride in advance made by L’Herminier, it is very disappointing for the historian to have to record that the next inquirer into the osteology of birds achieved a disastrous failure in his attempt to throw light on their arrangement by means of a comparison of their sternum. This was Berthold, who devoted a long chapter of his Beiträge zur

Anatomie, published at Göttingen in 1831, to a consideration of the subject. So far as his introductory chapter went—the development of the sternum—he was, for his time, right enough and somewhat instructive. It was only when, after a close examination of the sternal apparatus of one hundred and thirty species, which he carefully described, that he arrived (pp. 177-183) at the conclusion—astonishing to us who know of L’Herminier’s previous results—that the sternum of birds cannot be used as a help to their classification on account of the egregious anomalies that would follow the proceeding—such anomalies, for instance, as the separation of Cypselus from Hirundo and its alliance with Trochilus, and the grouping of Hirundo and Fringilla together.

At the very beginning of the year 1832 Cuvier laid before the Academy of Sciences of Paris a memoir on the progress of ossification in the sternum of birds, of which memoir an abstract will be found in the Annales des sciences naturelles (xxv. pp. 260-272). Herein he traced in detail, illustrating his statements by the preparations

he exhibited, the progress of ossification in the sternum of the fowl and of the duck, pointing out how it differed in each, and giving his interpretation of the differences. It had hitherto been generally believed that the mode of ossification in the fowl was that which obtained in all birds—the ostrich and its allies (as L’Herminier, we have seen, had already shown) excepted. But it was now made to appear that the struthious birds in this respect resembled, not only the duck, but a great many other groups—waders, birds-of-prey, pigeons, passerines and perhaps all birds not gallinaceous—so that, according to Cuvier’s view, the five points of ossification observed in the Gallinae, instead of exhibiting the normal process, exhibited one quite exceptional, and that in all other birds, so far as he had been enabled to investigate the matter, ossification of the sternum began at two points only, situated near the anterior upper margin of the side of the sternum, and gradually crept towards the keel, into which it presently extended; and, though he allowed the appearance of detached portions of calcareous matter at the base of the still cartilaginous keel in ducks at a certain age, he seemed to consider this an individual peculiarity. This fact was fastened upon by Geoffroy in his reply, which was a week later presented to the Academy, but was not published in full until the following year, when it appeared in the Annales du Muséum (ser. 3, ii. pp. 1-22). Geoffroy here maintained that the five centres of ossification existed in the duck just as in the fowl, and that the real difference of the process lay in the period at which they made their appearance, a circumstance which, though virtually proved by the preparations Cuvier had used, had been by him overlooked or misinterpreted. The fowl possesses all five ossifications at birth, and for a long while the middle piece forming the keel is by far the largest. They all grow slowly, and it is not until the animal is about six months old that they are united into one firm bone. The duck, on the other hand, when newly hatched, and for nearly a month after, has the sternum wholly cartilaginous. Then, it is true, two lateral points of ossification appear at the margin, but subsequently the remaining three are developed, and when once formed they grow with much greater rapidity than in the fowl, so that by the time the young duck is quite independent of its parents, and can shift for itself, the whole sternum is completely bony. Nor, argued Geoffroy, was it true to say, as Cuvier had said, that the like occurred in the pigeons and true passerines. In their case the sternum begins to ossify from three very distinct points—one of which is the centre of ossification of