B I R 



E I R 



other by means of a ligament, and have no conneAion what- 

 ever with the ftemum. 



The climicle is a ftraight bone in birds ; it does not lie 

 in a tranfverfe direction with refpcft to the trunk of the 

 body, but proceeds upwards and forwards towards the 

 lower part of the cervical fpine ; and in proportion to the 

 length and projedtion of the clavicle, the bird pofTefres 

 ftrength of wing and aflivity of flight. The clavicle at its 

 articulation with the fltrnnm is thin and broad ; but the 

 reft of the bone is of a round (hapc : it produces a procefs 

 from the pofterior part of its dorfal extremity, which is 

 united to the head of the fcapvda, and in conjunftion with 

 it, forms a depn-flion analogous to the glenoid cavity, al- 

 though not of the fame figure. The infide of the ex- 

 treme part of the dorfal end of the bone, is joined by liga- 

 ment with the branch of the fork, as already mentioned. 



The clavicles ot the Jirulhiie are remarkably lliort, and 

 zre anchylofed with the fcapulas at leaft. 



The fcitptiln are two long, plain bones, w'xxh (harp edges, 

 refembliiig, in a great degree, the blade of a knife ; tliey 

 lie parallel to the dorfal fpine, and have no proceffe':, ex- 

 cept the one which contributes with the clavicle to form 

 the cavity for lodging the head of the humerus; and a 

 little eminence oppofite to this, which feems analogous to 

 the acro7n'wn, and is joined to the end of the branch of the 

 fork. The fcapula:, like all tT>c other bones of the fhouldcr, 

 are very (hort m the Jlruihitr, not pafllng beyond the firft 

 two or three ribs ; although in many other birds thtfe 

 bones reach as far as the pelvis. 



The humeri:! is a round, fniooth bone, more or lefs en- 

 larged, and flattened at the e-ctremities ; the furface by 

 which it articulates wjth the foifa in the fcapula and cla- 

 vicle, is at the very end of the bone, and is firmed of a 

 portion of a cylinder, inftead of a fphere, which is moft 

 fuitable to the motions of the humerus in birds, they being 

 almoll confined to the elevation and deprefllon of the wing. 

 The external tuberofity of the humerus is verj' fmall ; but 

 the fpine which leads from it is greatly elevated in moll 

 fpecies of birds. The internal tuberofity is, on the other 

 hand, remarkably large, and furnifhes a procefs at its upper 

 part, which c.irrefponds, in fonie rdpefts, with the coracoid 

 procefs of the fcapula in mammalia. The humerus is lo.ig, 

 in proportion to the other bones of the wing in the African 

 ojlr'ich, and takes the curvature of the bird's bodv. It is 

 extremely (liort and fmall, and without procefles, in the 

 New Holland ojlr'uh, and cajfotviiry. 



The humerus is conneflvd with the bones of the fore arm 

 by an articular furt'^ace, fimilar to that of the Inmian fubjcft. 



The niilius is ulnally a much more (lender bone than the 

 ulna, with wliich it is never obferved to be anchylofed. 



The ulna exhibits no remarkable proceifes ; it forms a 

 pully on its lower end. Thefe two bones are flat in the 

 manchot [apteiiodjtit), and are joined by an articulation which 

 permits motion m ieveral directions, with two tubercles, one 

 above, and the other below tlie anterior edge of the lumie- 

 rus. The wirig of this bud, both. In its itructnre and of- 

 fices, refembles a fin. The ulna and radius are ncarlv of an 

 eqnal fize in \.\ie Jlrntbi^ ; they are butli very fmall, and 

 have but little motion on the humerus. 



There are but two carpal bones in birds ; one is applied to 

 the end of the radius, and prevents the motion of the lower 

 part of the wing beyond the line ot the radius; the other 

 moves a little upon the end of the ulna, to which its form is 

 adapted. It has often a little procefs from its lower edge, 

 which is analogous to the os pU'ifnrme. The carpal bones 

 are obliterated in \\\t Jlruthiuus birds. 



The metacarpus confills of two bones, which are united at 

 their fuperior part by anchylofis for fome way. At this 

 Vol, IV, 



place there are fome eminences wliich appear like the re- 

 mains of the fecond row of carpal bones foldered together. 

 The articulation of the metacarpus with the carpus is the 

 fegmout of more than the half of a pulley, which is grooved 

 in the middle, and revolves within a correfponding furface 

 of the lower carpnl bone. This motion, for the convenience 

 of defcription, is called flexion and extenfion ; but it is in 

 ftnftncfs a lateral movement back upon the ulna, and ac- 

 companied with a degree of rotation, by which the concave 

 figure of the wing is loft in the very aftioii of folding it. 

 There is a (lyloid procefs on the upper part of the radial 

 fide of the m.etacai-pus, which gives attachment to a fmall 

 pointed bone, fupplying the place of the thumb. A fimilar 

 bone is aflixed to the extreme end of the fmall branch of 

 the metacarpus, and correfponds to the little Jinger. The 

 principal, or fore Jinger, which terminates the wing, is arti- 

 culated with the large or radinl branch of the metacarpui. 

 It cor.fifts of two phalanges, and the firft exhibits marks of 

 having been originally two bones. The two pieces of the 

 metacarpus are to be feen in the African oflrich, as alfo the 

 three fingers ; each of which is iurnilhcd with a hook, which 

 is covered with a horn, like a claw ; but in the New Holland 

 cjlrich the metacarpus is a fingle bone, and there is but one 

 f nger, which is alfo terminated with a claw. All the bones of 

 the hand are compreffed into thin plates in the manchot. 



The thigh-bone of birds has nothing very peculiar in it* 

 fnnn ; it wants the fmall trochanter ; it is fingrlarly (hort, 

 in proportion to the other parts of the limb, in fuch birds as 

 have long legs ; it is longetl in the accipitres, and fhorteil in 

 fome water-birds. The femur is ftrong in all the gallinx; 

 and in the Jlruthiif it is of an immenfc thickntfs ; it is bent 

 in the cormorant and the little grebe. 



Tliere is a certain portion of the ligament of the extenfor 

 mufcles of the leg converted very early into bone ; and this 

 feems in general to fupply the place of the patella ; it is not 

 ufually preferved in ilcelctons. 



The tibia refembles in its form the fame bone in mamma- 

 lia. There are feveral prominent edges on the fire part of 

 its head for the attachment of mufcles. The lower end of 

 the tibia forms a pulley with a groove along the middle. 

 The head of the tibia is prolonged in a remarkable manner 

 upon the thigh, in the grebes and the diver. 



The fbula is a very fmall bone, and is foon anchylofed to 

 the fide of the tibia. 



The tarfus and metatarfus confift, in the adult bird, but 

 of one bone ; it exhibits, however, grooves coirefponding to 

 the divifions which exifted between its feveral pieces when 

 it was firft formed. Thefe are ftrongly marked in the long- 

 leg red birds, and fliew that the metatarfus contained origi- 

 nally as many bones as there are principal toes. There is 

 ufually aho a prominence on the pofterior part of the head 

 of the bone wliich reprefents the os calcis. The inferior ex- 

 tremity of the metatarfal bone produces a procefs (haped 

 like a pulley for the articulation with each of the principal 

 toes 



There are three bones in the compofition of the tarfusand 

 metatarfus of the manchot feparate from each other in the 

 middle ; and therefore thefe birds are plantigrade, or walk 

 upon the metatarfus as well as the toes. 



The extraordinary length of limb which belongs to fome 

 kinds, as thejlruthious and ouaJing birds, depends upon the 

 extent of the tibia and metatarfal bone. 



The Jlork, and fome others of the gralla, which deep 

 ftanding on one foot, poffcls a curious mechanifm for prei 

 ferving the leg in a ftate of extenfion, without any, or at 

 leaft with little mulcular effort. There arifes from the fore 

 part of the head of the metatarfal bone a round eminence, 

 which paffes up betweca the projeftions of the pulley on the 

 J I anterior 



