BIRDS
ANATOMY OF BIRDS.
IN the consideration of the Anatomy of Birds, classi fication will be quite a secondary matter, and merely employed for the elucidation of internal structure. Some sort of grouping, however, is indispensable; and that is accordingly adopted, as the most convenient for the morpho- logist, which was first proposed by Professor Huxley,[1] with the introduction of certain modifications rendered necessary by the present writer s own researchesresearches, it may be added, which have been carried on in constant com munication with that investigator.
A little examination will show that the groups made by consideration of any, even the most important, morpho logical modifications, cannot be superimposed upon groups made by reference to the whole sum of the characters of the Bird. This may be easily explained. About half the known Birds, 5000 or thereabouts, belong, according to G. B. Gray, to Professor Huxley s group, the Coraco- morphce. These birds undergo a peculiar metamorphosis of the naso-palatal structures, and are called by Pro fessor Huxley the dSgithognathoe on that account. Now all the Coracomorphce have the segithognathous palate, but so also have the CypselidcB, or Swifts, which are placed by this author with the Humming-birds and Goatsuckers, both of which groups are simply schizognathous. Moreover, below the Passerine types, and only next above the Semi- Btruthious Tinamous, we find the Hemipods, Turnicidce, or Turnicimorphce, and these have an segithognathous palate. So also has another type, Thinocorus, which lies on the same low zoological level as the Hemipods. This latter bird is essentially a small Geranomorph, but it is below the true Cranes, and unites in its palate characters belonging to the Ostriches below it and the Passerines which ascend, zoologically, far above it.
The difficulty of applying this very valuable morpho logical grouping, and making it fit in with one that is more general and distinctively zoological (that is, having reference to every character, external, and internal), does not take away anything of real value from it. To the anatomist such a mode of viewing the various types is perfectly natural, however hard it may be to satisfy the pure zoologist as to its great value. Certainly, the struc tures of the skull and face govern the whole body, as it were ; every other part of the organism corresponds to what is observable there. Nor must it be forgotten that the true mode of studying any kind of creature is that of its development; and the head undergoes the most remark able morphological changes.
In the following scheme we have added one new mor phological group to Professor Huxley s classification. This group includes the Woodpeckers and Wrynecks, Picidce and Yungidae. Zoologically it forms the family Celeo- morphce (Huxley) ; its morphological term is Saurognathce (Parker).
Every one who has laboured at the anatomy of this class must have been struck by its marvellous uniformity ; almost countless numbers of species are found passing insensibly into one another, and differing in the slightest manner. The best modern zoologists are at times almost at their wits end to know by what characters they may distinguish their genera and species. This has been well put by Professor Huxley (Anat. of Vert. Anim.) He says (p. 272) " Though this class contains a great number of specific forms, the structural modifications which they present are of comparatively little importance ; any two birds which can be selected differing from one another far less than the extreme types of the Lacertilia, and hardly more than the extreme forms of the Chelonia, do. Hence the characters by which the following groups" (see subjoined table) "are separated appear almost insignificant when compared with those by which the divisions of the Reptilia are indicated."
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MORPHOLOGICAL CLASSIFICATION OF BIRDS. A. The metacarpals not ankylosed together. The tail longer than the body. I. SAUKUR.fi. 1. Arc/ucopterygidce. B. The metacarpals ankylosed together. The tail considerably shorter than the body. A. The sternum devoid of a keel. II. RATITJS. a. The wmg with a rudimentary, or very short, humerus, and with not more than one ungual uhalanx. o. A hallux. 2. Aptcrygidce (the Kiwis). 18. No hallux. 3. DinornitMdee (the Moas). 4. Casuariidce (the Cassowaries and Emeus). b. The wing with a long humerus, and with two ungual phalanges. a. The ischia uniting immediately beneath the sacrum, and the pubes free. 5. RJif.idce (the American Ostriches). B. The ischia free, and the pubes uniting in a ventral symphysis. 6. Struthionidce (the Ostriches). B. The sternum provided with a keel.[2] III. CAUINAT.E. a. The vomer broad behind, and interposing between the pterygoids, the palatines, and the basi-sphenoidal rostrum (Dromseognathae). 7. Tinamomorphce (the Tinamous). b. The vomer narrow behind ; the pterygoids and pala tines articulating largely with the basi-sphenoidal rostrum. a. The maxillo-palatines free.[3] i. The vomer pointed in front (Schizo- gnathas). 8. Cha/radriomorphce (the Plovers). 9. Cecomorphce (the Gulls). ^0. Sphcniscomorphce (the Penguins). 11. Geranomorplice (the Cranes).[4] 12. Alcctoromorphce (the Fowls). 13. Pteroclomorphce (the Sand-Grouse). 14. Peristeromorphce (the Pigeons). 15. Heteromorphce (the Hoazins). 16. Coccygomorphce (part), (the Goatsuckers). 17. TrochilomorpTuK (the Humming-Birds). ii. The vomer truncated in front thognathee). 18. GeranomorphoB (part), (the exceptional sub family IVwHOcomice/fhinocorus). 19. TurnicomorphcB (the Hemipods). 20. Cypsdomorphce (the Swifts). 21. Coracomorphce (the Passerines). iii. The vomerine halves permanently dis tinct, and the rnaxillo-palatines ar rested (JSaurognathse). 22. Cdcomorphcc (the Woodpeckers). 8. The rnaxillo-palatines united, either by coa lescence with the ossified septum nasi ; or, 2d, by meeting at the mid-line and form ing a suture ; or, 3d, in the fullest degree, by complete ankylosis of the right and left plates. 23. AdomorpluE (the Birds of Prey). 24. Psittacomorphee (the Parrots). 25. Coccygomorphce (the Cuckoos, Kingfishers, and Trogons). 26. ChenomorphoB (the Anserine Birds). 27. AmpMmorphee (the Flamingoes). 28. Pdargomorphas (the Storks). 29. Dysporomorphcc (the Cormorants).
- ↑ " On the Classification of Birds ; and of the taxonomic value of the modifications of certain of the cranial bones observable in that class," Proceedings of the Zoological Society, April 11, 1867, pp. 415-472. This classification is somewhat modified in a later paper by the same author, in which a very masterly description is given of the Gallinaceous group (Alectoromorphcc, Huxley), " On the Classifica tion and Distribution of the Alectoromorphcc &nd Heteromorphce," ibid.. May 14, 1868, pp. 293-319. The same author repeats, in essentially the same form, the original classification in his Anatomy of the Verte- brated Animals (1871, p. 272). The materials from which the modi fied views here given have been taken are in a series of contributions by Mr Parker to the Transactions of the Linnean and Zoological Societies now (1875) passing through the press. For figures of the skeleton see Mr Eyton s Oitcologia Avium.
- ↑ The keel is but little developed in Strigops (Psittac-tdce], in Didu (Dididce), and in Aptornis (Eallidce].
- ↑ Professor Huxley here gives in a note two exceptions, namely, Crax and Dicholophitx. The latter bird, the Cariama, is, however, as Mr Parker has shown, a low, gruiform, rapacious bird, having its maxillo-palatines united by suture, and being an example of a bird with imperfect direct desmognathism.
- ↑ With the exception of Thinocorus, see below.
