Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/733

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skull.]
BIRDS
715

types. "Basi-pterygoid processes [and vorners] are want- in r . The palatines are vertically elongated posteriorly, while anteriorly they are horizontally flattened, and movably united with the rostrum. The inaxillo-palatines are spongy. The lachrymal and post-orbital bend towards one another, and frequently unite below the orbit." This is by the intervention of a large "03 uncinatum," which is best seen in small types, such as Psephotis multicolor, and Agapornis pullaria, where this part does not unite with the post-frontal. In Microglossa, Calyptorhynchus, Plycto- lopJius, Melopsittacus, <fcc., the temporal fossa is also bridged over by junction of the zygomatic process of the squamosal with the os uncinatum. " The orbital process of the quadrate bone is very small, and its distal presents only one facet (which is compressed from side to side, and convex from before backwards) for the mandible. The rami of the latter are deep, and pass into one another by a rounded symphysis." The glosso-hyal is spatulate, and the basi-hyal is alate behind. In the fore-face are some things worth noting. The septum nasi is a thick wall of bone ; the alse nasi are soft in Psephotis multicolor; they have an annular ossicle found in them in Melopsittacus undulatus ; whilst in Palceornis torquata this part is largely ossified and ankylosed to the upper jaw, and the alinasal turbinal is partly calcified. In one small kind we saw the trace of a small medio-palatine. The pars plana is narrow and ossified, and is ankylosed to the lachrymal ; the inferior

turbinal is soft.

7. The Coccygomorphæ.—This is another polymorphic group, and is not in any sense, either zoologically or mor phologically, the equivalent of the last. Yet it is almost impossible to separate the families by any character of importance. If the Podargus must be linked with the Kingfisher, the Goatsucker and its allies cannot be re moved, notwithstanding their schizognathous palate. Here, however, we are dealing with the desmognathous forms. Professor Huxley makes four sub-groups, and then remarks (p. 467) : " It appears to me not improbable that it may hereafter be desirable to divide this group into four." The characters of the skull are thus given (p. 4GG) : " The rostrum presents very various forms, and may be movably articulated with the skull. Basi-pterygoid processes are present in only one genus (Trogon)."[1]

The Oil-bird (Steatornis caripensis) has very large b-isi-pterygoids, thus connecting the Goatsuckers with Podargus. " The maxillo-palatines are usually more or less spongy. The palatines are not developed into vertical plates, but are, as usual, horizontally flattened. The distal end of the quadrate has the ordinary form." The vomer is small in Hornbills, Toucans, and Scythrops ; but they have a second bone in front of the azygous vomer, viz., tho " median septo-maxillary," as in the Goose tribe and others. In Podargus, when the lower palatine floor like that of a Mammal is cut away, there are to be seen three small ossicles ; the first of these is the vomer, the others are medio-palatines. In Megalcema the vomer is very large and forked in front. In the Kingfishers and Hoopoes there is no vomer ; there is a trace in Corythaix. The palatines may be rounded behind as in Cuculus and Buceros, have a retral spur to the transpalatine part as in Rhamphastos Alcedo, and Upupa, or be very broad, with a large passerine trauspalatine angle, as in Podargus.[2]

The Ægithognathous TypeCranium of the RookThis figure and its description must do duty for the whole of the jEgithognathce, which, with a little cutting and contriv ing, may be made to cover the CoracomorphcB entirely, with enough at its corners also to be superimposed upon the Swifts and the Hemipods, and that remarkable charadrian bird, Thinocorus.[3] It is worth while to remember that these types are actually the highest, the most metamor phosed, and the most specialized ; not so high in some respects as the Mammal, yet no Mammal comes near them in adaptive modification, not even the one which has the taste to admire, and the wit to describe them. We learn from no less an authority than Mr G. R. Gray that of the 10,000 known birds half belong to this group ; the Old World types of which, more especially, are such accom plished creatures. The Nectarinia is the smallest, and the Raven the largest of this huge, but morphologically very uniform, group.

The skull of a fledgling Rook (fig 26) illustrates the highest bird of this type ; the occipital condyle (o.c.) is hemisphe rical, the basi- temporal plate (b.t.) is an almost transverse band of bone, the rostrum of the parasphe- noid (pa.s.) is without any de veloped basi-ptery goids, the cranio- facial hinge is nearly perfect, but the nasals and nasal processes of the premaxillaries are thin splints set into the f rentals ; they do not form a perfect hinge.

The palatines are developed into cartilage at their hinrlprinrrlp f-Tiio Uiuuei dllgie , iiiis> is a large flap, and, ossifying late and separately, has time to become chondrified first (t.pa.) ; the pterygoids (pg.) are phalangiform, and lose their meso-pterygoid spur, which soon coalesces with the palatines. The maxillo-palatine processes are hooked and flattened, and often enlarged at their inner extremity, so as to become pneumatic.


FlG - 20. Skull of nestling Rook (Corrui frugilegus),

palatal view, natural size. The prenasal region (p.n.) is trifoliate; the median rod, looking for wards, is the remains of the prenasal or basi-trabecu- lar bar ; the lateral leaves of cartilage, looking back wards, are the recurrent ventral extremities of the trabecular cornua: between the alinasai tui binals the base of the septum nasi retains its flatness ; it is formed by the inter-nasal part of the trabeculae.

But the distinguishing character of the type is the union

  1. For a figure of this skull, see Professor Reinhardt s paper on the "Os uncinatum" (" Om en hidtil ukjendt Knogle i Hovedshallen hos Turakoerue Musophagidcs, Sundev," Scertryk af " Videnskabehye Meddelelser fra den yaturhistoriske Forening I KjrJbenham," 1871). In this paper figures are given of the skull of Corythaix, Muaophaya, Schizorhit, and Trogon.
  2. See Professor Huxley s figures, those of M. Reinhardt just referred to, and Dr Murie s valuable papers "On the Skeleton of Todus," Proc. Zool. Soc., May 21, 1872, plate 55, pp. 663-G30 ; "Ou the Genus Colim," The Ibis, July 1872, plate 10, pp. 261-280 ; " On the Motmots," Ibis, Oct. 1872, plates 13-15, pp. 383-412; "On the Upupidce," Ibis, April 1873, plates 5-7. pp. 181-211.
  3. For descriptions of the skulls of Passerine birds, see Parker on the "Skull of the Crow," Monthly Micr. Jour., Nov. 1, 1872 ; on that of the "Tit" (Parus^i, ibid., Jan. 1, 1873; and on that of the " Thrush," ibid., Mar. 1, 1873. See also, as referred to by Professor Huxley, Nitzsch s article " Passerinse " in Ersch and Gruber s Encyclopedic, 1840, and his paper. " Ueber die Familie der Passerinen," in the Zeitschrift fur die Gesammten Naturwissenschaften, 1862. As the figure given above is of a young bird, the reader is also referred to Professor Huxley s " Palatal View of the Raven s Skull" (op. cit., p. 451, fig. 32) ; of that of the " Grosbeak," fig. 33 ; and of the " Swift, 1 tier. 34. gee also Murie "On Fregilupus," Proc. Zool. Soc., June 16, 1874, plates 61. 62.