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The most novel feature, and one the importance of which most ornithologists of the present day are fully prepared to admit, is the separation of the class Aves into two great divisions, which from one of the most obvious distinctions they present were called by its author Carinatae and Ratitae, according as the sternum possesses a keel (crista in the phraseology of many anatomists) or not. But Merrem, who subsequently communicated to the Academy of Berlin a more detailed memoir on the “flat-breasted” birds, was careful not here to rest his divisions on the presence or absence of their sternal character alone. He concisely cites (p. 238) no fewer than eight other characters of more or less value as peculiar to the Carinate Division, the first of which is that the feathers have their barbs furnished with hooks, in consequence of which the barbs, including those of the wing-quills, cling closely together; while among the rest may be mentioned the position of the furcula and coracoids, which keep the wing-bones apart; the limitation of the number of the lumbar vertebra to fifteen, and of the carpals to two; as well as the divergent direction of the iliac bones—the corresponding characters peculiar to the Ratite Division being the disconnected condition of the barbs of the feathers, through the absence of any hooks whereby they might cohere; the non-existence of the furcula, and the coalescence of the coracoids with the scapulae (or, as he expressed it, the extension of the scapulae to supply the place of the coracoids, which he thought were wanting); the lumbar vertebrae being twenty and the carpals three in number; and the parallelism of the iliac bones.

As for Merrem’s partitioning of the inferior groups there is less to be said in its praise as a whole, though credit must be given to his anatomical knowledge for leading him to the perception of several affinities, as well as differences, that had never before been suggested by superficial systematists. But it must be confessed that (chiefly, no doubt, from paucity of accessible material) he overlooked many points, both of alliance and the opposite, which since his time have gradually come to be admitted.

Notice has next to be taken of a Memoir on the Employment of Sternal Characters in establishing Natural Families among Birds, which was read by De Blainville before the Academy of Sciences of Paris in 1815, but not published in full for more than five years later (Journal de physique et des arts, xcii. 185–215), though an

abstract forming part of a Prodrome d’une nouvelle distribution du règne animal appeared earlier (op. cit. lxxxiii. 252, 253, 258, 259; and Bull. soc. philomath. de Paris, 1816, p. 110). This is a very disappointing performance, since the author observes that, notwithstanding his new classification of birds is based on a study of the form of the sternal apparatus, yet, because that lies wholly within the body, he is compelled to have recourse to such outward characters as are afforded by the

proportion of the limbs and the disposition of the toes—even as had been the practice of most ornithologists before him! It is evident that the features of the sternum of which De Blainville chiefly relied were those drawn from its posterior margin, which no very extensive experience of specimens is needed to show are of comparatively slight value; for the number of “échancrures”—notches as they have sometimes been called in English—when they exist, goes but a very short way as a guide, and is so variable in some very natural groups as to be even in that short way occasionally misleading. There is no appearance of his having at all taken into consideration the far more trustworthy characters furnished by the anterior part of the sternum, as well as by the coracoids and the furcula. Still De Blainville made some advance in a right direction, as for instance by elevating the parrots and the pigeons as “Ordres,” equal in rank to that of the birds of prey and some others. According to the testimony of L’Herminier (for whom see later) he divided the “Passereaux” into two sections, the “faux” and the “vrais”; but, while the latter were very correctly defined, the former were most arbitrarily separated from the “Grimpeurs.” He also split his Grallatores and Natatores (practically identical with the Grallae and Anseres of Linnaeus) each into four sections; but he failed to see—as on his own principles he ought to have seen—that each of these sections was at least equivalent to almost any one of his other “Ordres.” He had, however, the courage to act up to his own professions in collocating the rollers (Coracias) with the bee-eaters (Merops), and had the sagacity to surmise that Menura was not a Gallinaceous bird. The greatest benefit conferred by this memoir is probably that it stimulated the efforts, presently to be mentioned, of one of his pupils, and that it brought more distinctly into sight that other factor, originally discovered by Merrem, of which it now clearly became the duty of systematizers to take cognizance.

Following the chronological order we are here adopting, we next have to recur to the labours of Nitzsch, who, in 1820, in a treatise on the nasal glands of birds—a subject that had already attracted the attention of Jacobson (Nouv. Bull. soc. philomath. de Paris, iii. 267–269)—first put forth in Meckel’s Deutsches Archiv für die Physiologie (vi.

251-269) a statement of his general views on ornithological classification which were based on a comparative examination of those bodies in various forms. It seems unnecessary here to occupy space by giving an abstract of his plan, which hardly includes any but European species, because it was subsequently elaborated with no inconsiderable modifications in a way that must presently be mentioned at greater length. But the scheme, crude as it was, possesses some interest. It is not only a key to much of his later work—to nearly all indeed that was published in his lifetime—but in it are founded several definite groups (for example, Passerinae and Picariae) that subsequent experience has shown to be more or less natural; and it further serves as additional evidence of the breadth of his views, and his trust in the teachings of anatomy.

That Nitzsch took this extended view is abundantly proved by the valuable series of ornithotomical observations which he must have been for some time accumulating, and almost immediately afterwards began to contribute to the younger Naumann’s excellent Naturgeschichte der Vögel Deutschlands, already noticed above. Besides a concise general treatise on the organization of birds to be found in the Introduction to this work (i. 23-52), a brief description from Nitzsch’s pen of the peculiarities of the internal structure of nearly every genus is incorporated with the author’s prefatory remarks, as each passed under consideration,