Page:Encyclopædia Britannica, Ninth Edition, v. 3.djvu/734

of the vomers with the alinasal wall and turbinal, and the possession, by the embryo bird at least, of a pair of " upper labials/ corresponding to the inner upper pair in Snakes, Sharks, and Skate ; the vomers are either partial or entire ossification of these cartilages. Besides these, there re appear in most of the uEgithognatkce the so-called " inferior turbinals," or nostril-bones of the Snake and Lizard, and these are attached to the shoulders of the double, and generally, ox-face-shaped vomer.^[1] The nasal labyrinth is very large in the Rook, but does not differ in essentials

from that of the Fowl, above described.

The septum nasi (s.n.) retains much of its original flat ness below, and is thus alate ; the vomer (v.) of the young bird is broad and grooved above ; in the old bird, ossifi cation running some distance along the alinasal wall and alinasal turbinal (n.tb.), the bone becomes not only emar- ginate, but also very massive in front. In the Lark (A lauda arvensis) this bony matter in the macerated skull leaves huge goat-horn processes to the fore-angles of the vomer. jEgithognathism occurs in different degrees ; thus, we may have its morphological conditions—

a. Incomplete : as in Turnix.

b. Complete var. 1 : Pachyrhamphus, Pipra.

c. Complete var. 2 : Corvus, Alauda.

d. Compound : Gymnorhina, Artamus.

a. Incomplete. Here the large " labials" are imper fectly ossified by the two vomcrs, and these bones are only strongly attached to the nasal labyrinth by fibrous tissue.

b. Complete var. 1. In these cases the labials are often only imperfectly ossified by the vomerine centres ; these centres also are distinct from those ossifying the alinasal cartilages ; but the union of these parts is perfect.

c. Complete var. 2. In these cases the labials are often small and completely ossified by the vomers ; but the bony deposit runs riot into the alinasal wall and turbinal, so that in the adult all distinction of the parts may be lost.

d. Compound. Here the flat arcuate end of the maxillo- palatine is free, but the mass of that plate meets its fellow of the opposite side and coalesces with it, and with a highly ossified nasal septum. In these Southern types the " transpalatine" is a long spike, as in the Alcedida;. In all these varieties the septo-maxillaries may, and do mostly, occur. They cannot always be found.^[2]

Concluding our remarks upon this morphological type, its value is shown by this that it is exactly superimpos- able upon the Coracomorphce, if "we reject the bird that shows its initial or imperfect condition, as the Hemipod, and stubbornly hold to the popular view that Swifts are a kind of Swallow for as to their nobler part, their head, they are merely a variety of that type. Thus the zoologist and the morphologist may here join hands.

The Saurognathous Type—Cranium of the Picus Minor.—This group, Professor Huxley s Cdeomorphae (op. cit. 448 and 467), is so remarkable and difficult of deter mination, that although our author saw clearly many most important characters (quite sufficient for the elimination of this group from the Cocrygomorphce), yet the materials at hand were not sufficient for a perfect account of this type of skull. A fellow-worker has had fuller opportunities.^[3] Like the Parrots, these birds form a relatively small and neat group; the most outlying forms are Picumnus and Ytituc, but these form no obstruction to their classification. Mr Parker s proposed morphological term for these birds is Saurognath(B, and the two terms can be superimposed, Celeomorphce being their zoological name. Professor Huxley saw that these birds were not desmognathous ; that their vomerine moieties remained distinct ; that their maxillo- palatines are but little developed ; and that supernumerary bones on the inner edge of the palatines in Picus minor corresponded to the curious bars that are seen in the larger kinds. He also, with quick insight, says that their palate exhibits a " degradation and simplification of the ^Eg-itho- gnathous structure." This is strictly true ; the elementary parts are the same, but in the Woodpeckers they retain a very Reptilian distinctness, and even arrest of growth. Yet with that arrest there is combined a modification and metamorphosis of certain parts, such as is undergone by no other type. They are in some respects the most simple and embryonic, and in others the most highly specialized birds in the whole class. Their basi-pterygoids are arrested; their basi-temporal region large and wide. Two or three tympanics on each side help to form their remarkable cowrie-shaped ear-drum, which is mainly built up by the basi-temporals and exoccipitals. The lower end of the quadrate has the usual form : the bone itself is short ; the pterygoids are long, slender, angular, and forked ; the lower and foremost fork is the meso-pterygoid element, which does not become segmented otf, and thus their pterygoids answer to that of a Snake or Lizard, and reach to the vomer.^[4]

FIG. 27.- -Palatal view of skull of a ncstHnR of Picus miner, X 4 ammeter*,

fpa, inter-palat jne spur ; t.mx.. septo-maxillary ; tn.pa., medio-palatine.

The palatines (fig. 27, pa.) have their postero-external

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1. There is not space here to give illustration of all these details ; but papers by Mr Parker are now (1875) appearing in the Transactions of the Linnean and Zoological Societies, in which these structures are copiously illustrated.
2. Professor Huxley (op. cit., p. 472) was as unfortunate in his specimen of Menura as in that of Trochilus (see p. 468, where these birds are said to have their vomer truncated, whereas it is spiked) ; for in Mr Garrod s specimens of the Lyre-bird s skulls the maxillo palatines are large bony plates, like those of ordinary Coracomorphce The vomer of Menura is exactly like that of the Chough ( Frcgilus graculus), and also of many young Coracomorphce, for the two moieties do not necessarily form a re-entering angle or notch in front ; that is often largely due to the osseous growth creeping into the alinasal cartilages. Menura has one character of great importance, viz., it retains the super-orbital chain of ossicles, like Psophia and the Tqfwqffqeqw
3. See Mr Parker s paper " On the Picidce," in the Linnean Transactions, 1875, series 2, vol. i. plates 1-5.
4. See Giinther " On Hattena" Phil. Trans., 1867, plate ] , fig 2> p. 5.