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ORTOLAN. Its good qualities have been described at length by Alexander Wilson, Nuttall, and Audubon, to say nothing of more recent writers on North-American ornithology, and to those authors must reference be made for its description and an account of its habits. From the purely scientific point of view the form is one of considerable interest, as it seems to connect the Emberizidæ (BUNTING) with the Icteridæ (GRACKLE, ICTERUS); and, though generally considered to belong to the latter, is rather a divergent member of that Family. It is a bird that performs vast migrations, breeding as high as lat. 54° N., and in winter visiting the Antilles and Central and South America as far as Paraguay.

BOB-WHITE, a nickname of the Virginian Quail, Ortyx virginianus, aptly bestowed from the call-note of the cock.

BONE or osseous tissue consists of phosphate and carbonate of lime, salt, and a few other earthy substances. Hollow bones contain marrow, a fatty substance with delicate connective tissue, except where it has been driven out by the penetrating AIR-SACS. On the surface of a bone, covered by a fibrous membrane, the periosteum, there open small, often microscopic, holes, which as “Haversian Canals” are continued through the walls of the bone into larger spaces or cancelli, and ultimately into the marrow cavity. These render possible the entrance of blood-vessels, air-cells, and nerves. Bones which have their entire substance or diploe between the outer and the inner lamella filled with cavities and cancelli are called cancellated or spongy; this is especially the case in the bones of the head of Owls, and to an enormous extent in the “horn ” of the Hornbills. The bony substance forms consecutive layers around the Haversian canals. The layers themselves contain numerous irregular lacunæ, formerly but wrongly called bone-corpuscles, from which radiate numerous extremely fine canaliculi; these communicate with those of neighbouring lacuna and with the Haversian canals, securing thus access of blood and lymph to any part of the bone.

Bone is never directly formed out of the indifferent embryonic tissue, it always passes through a stage of connective tissue. If this tissue ossifies directly, it becomes a primary or membrane bone ; if the tissue is cartilage and finally supplanted by bony tissue, the latter forms a secondary or cartilage bone. Most of the bones of a bird's skeleton pass during their development through such a cartilaginous stage. Membrane bones are principally some of those forming the cranium, as the parietal, frontal, maxillæ, and vomer. Bones which are developed in tendons by direct ossification are termed sesamoid bones, as the brachial and the crural patella. Either kind of bone can ossify from various centres, but these “centres of ossification” do not necessarily indicate that the bone in question is composed of a number of originally separate bones. In long bones especially the shaft ossifies first, while the ends remain for a long time cartilaginous as “epiphyses” and eventually ossify often from a centre of their own, and are only in the adult completely fused with the shaft, forming the articulating facets, or projecting “processes” for the attachment and leverage of muscles.

BONXIE, the name by which the Great Skua, Stercorarius catarrhactes, is known in some of the Shetland Islands, its only British habitat.

BOOBY, said by Prof. Skeat (Etymol. Dict.) to be derived from the Spanish or Portuguese boboa fool, and that from the Latin balbus-stuttering or inarticulate, a name applied, most likely by our seamen originally, to certain birds from their stupidity in alighting upon ships and allowing themselves to be easily taken by the hand. The Boobies are closely allied to the GANNET, and indeed can hardly be separated from the genus Sula, though they differ in having no median stripe of bare skin down the front of the throat, and they almost invariably breed upon trees instead of rocks, and are inhabitants of warmer climates. One of them, S. cyanops, when adult has much of the aspect of a Gannet, but S. piscator is readily distinguishable by its red legs, and S. leucogaster by its upper plumage and neck of deep brown. These three are widely distributed within the tropics, and are in some places exceedingly abundant. A fourth, S. variegata, which seems to preserve throughout its life the spotted suit characteristic of the immature S. bassana, has a much more limited range, being as yet only known from the coast of Peru, where it is one of the birds which contribute to the formation of guano.

BOWER-BIRD, Gould's rather poetical name for some inhabitants of Australia which, while he was in that country he ascertained,” as on his return he announced (25 August, 1840) to the Zoological Society, to have the extraordinary habit of building what the colonists commonly called “runs.” “ These constructions”, he rightly said (Proc. Zool. Soc. 1840, p. 94), “are perfectly anomalous in the architecture of birds, and consist in a collection of pieces of stick or grass, formed into a bower; or one of them (that of the Chlamydera) might be called an avenue, being about three feet in length, and seven or eight inches broad inside ; a transverse section giving the figure of a horse-shoe, the round part downwards. They

Thus Purchas in his account of Davis's Second Voyage to India, in 1604-5, tells (Pilgrimes, I. bk. iii. p. 132) of “fowles called Pashara boues ”—which correctly spelt would be Paxaros bobos—at the island of Fernando Norhona. Later examples are too numerous to cite.

? The discovery seems to have been mainly due to the late Mr. C. Coxen of Brisbane.

are used by the birds as a playing-house or run,' as it is termed, and are used by the males to attract the females. The 'run' of the Satin-bird is much smaller, being less than one foot in length, and moreover differs from that just described in being decorated with the highly-coloured feathers of the Parrot-tribe; the Chlamydera, on the other hand, collects around its 'run'a quantity of stones, shells, bleached bones, etc.; they are also strewed down the centre within.”

This statement, marvellous as it seemed, has been proved by many subsequent observers to be strictly true, and it must be borne in mind that these structures, each of which as above described he next year (1 Sept. 1841) figured (B. Austral. iv. pls. 8, 10), have nothing to do with nests of the birds—indeed, their mode of nidification, which was not made known until some years later, presents no extraordinary feature. Moreover, the birds will build their “bowers” in confinement, and therein disport themselves, as has been repeatedly shewn in the Zoological Gardens 2 by the Satin-bird last mentioned, Ptilorhynchus violaceus. Subsequently it was found that the Regent-bird, Sericulus melinus, a species long before known, had the habit of making a “bower” of similar kind, though built, so to speak, in another style of architecture, and having for its chief decoration the shells of a small species of Helix.

The account of these curious birds which may be most conveniently consulted is that in Gould's Handbook to the Birds of Australia (i. pp. 441-461), published in 1865 ; but since that time discoveries still more wonderful have been made. A bird of New Guinea, originally referred to the genus Ptilorhynchus, but now recognized as Amblyornis inornatus, has been found by Sign. Beccari to present not only a modification of bower-building, but an appreciation of beauty perhaps unparalleled in the animal world. His interesting observations (Annali del Mus. Civ. de Storia Nat. di Genova, ix. pp. 382-400, tav. viii.) shew that this species, which he not inaptly calls the “Gardener" (Gjardiniere), builds at the foot of a small tree a kind of hut or cabin (capanna) some two feet in height, roofed with orchid-stems that slope to the ground, regularly

1 Gould brought home with him at least two examples, which he gave to the British Museum. There is no reason to suppose that this extraordinary habit had been described before the date above given, or that the name “ Bower-bird” had been previously used, and yet we find Trelawny in his Memoirs of Shelley, published in 1878, referring to himself (i. p. 136) as saying, in a conversation not later than 1822, “You two have built your nest after the fashion of the Australian bower-birds"!

? The ordinary visitor to these gardens seems to regard the structures of the Bower-birds without any intelligent interest. He perhaps supposes that they are the handiwork of one or other of the keepers. From my own long connexion with the Zoological Society, I think I am able to state that neither in this nor anything else of the kind is any deception practised. The Bower-birds are supplied with materials, and that is all.

radiating from the central support, which is covered with a conical mass of moss, and sheltering a gallery round it. One side of this hut is left open, and in front of it is arranged a bed of verdant moss, bedecked with blossoms and berries of the brightest colours. As these ornaments wither they are removed to a heap behind the hut, and replaced by others that are fresh. The hut is circular, and some three feet in diameter, and the mossy lawn in

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“GARDEN” OF AMBLYORNIS. (After Beccari. From The Gardeners' Chronicle, N.S., vol. ix. p. 333.) front of it of nearly twice that expanse. Each hut and garden are, it is believed, though not known, the work of a single pair of birds, or perhaps of the male only; and it may be observed that this species, as its trivial name implies, is wholly inornate in plumage. Not less remarkable is the more recently described

Another species referred to the same genus, A. subalaris, the female of which was originally described by Mr. Sharpe (Journ. Linn. Soc. xvii. p. 40) as being still more dingy, turned out to have the male embellished with a wonderful crest of reddish-orange (Finsch and Meyer, Zeitschr. f. ges. Orn. 1885, p. 390, tab. xxii.).

“bower” of Prionodura, a genus of which the male, like the Regentbird, is conspicuous for his bright orange coloration. This structure is said by Mr. Devis (Trans. Roy. Soc. Queensland, 14 June 1889) to be piled up almost horizontally round the base of a tree to the height of from 4 to 6 feet, and around it are a number of hut-like fabrics, having the look of a dwarfed native camp. Allied to the forms already named are two others, Scenopaus and Ailurcedus, which, though not apparently building “bowers,” yet clear a space of ground some 8 or 9 feet in diameter, on which to display themselves, ornamenting it “with tufts and little heaps of gaily tinted leaves and young shoots” (Ramsay, Proc. Zool. Soc. 1875, p. 592). The former of them, which, according to Mr. Lumholtz (Among Cannibals, pp. 139, 140), covers a space of about a square yard with large fresh leaves neatly laid, and removes them as they decay, inhabits Queensland, and to the latter belongs the “Cat-bird,” so well known to Australians from its loud, harsh, and extraordinary cries.

By most systematists these birds are placed among the Paradiseidæ (BIRD-OF-PARADISE); but in the British Museum Catalogue of Birds (vi. pp. 380-396) they are to be found in the “limbo large and broad” of Timeliida—though allowed the rank of a subfamily Ptilonorhynchinæ," the name being taken from the feathered and not the bare (as might from itsety PTILORHYNCHUS VIOLACEUS.

(After Swainson.) mology have been expected) condition of the base of the bill shewn in the figure of that part in the Satin-bird.

BRACHIAL ARTERY, see VASCULAR SYSTEM : BRACHIAL PLEXUS, see NERVOUS SYSTEM.

BRAIN, the part of the Central NERVOUS SYSTEM which is enclosed by the cranium, and in Birds consists of three principal divisions, named after their position—Hind- Mid- and Forebrain. The hindbrain is composed of the medulla oblongata, the direct and comparatively little modified continuation of the spinal cord, and of the cerebellum, these two parts being connected with each other by the pedunculi or crura cerebelli. The midbrain contains the peduncles of the great or forebrain, and the cortex or rind of the optic lobes. The forebrain is subdivided into the thalamencephalon and into the cerebral hemispheres. The ventral parts of the thalamencephalon form the hypophysis and the chiasma or crossing of the optic nerves, the lateral parts contain the inner portions of the optic lobes, which are partly homologous with

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