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order tliat the tnmk of the body may not be affsded by the 

 motions of the wings in flight. 



Tlicir fpinous procefTcs are commonly ar.chylofcd with 

 each otliT, which fometimes occurs alfo with rtfpeft to 

 the trnnfv<.He proccfies. In the cjlrich and cujoivtiry, the 

 proccfTts of the dorfal vertcbrK are diftindt, and poffefs a 

 degree <)f motion from which liowcver thefe birds cannot fuf- 

 fir any inconvenience, as they do not fly. 



The aiiM' vcrlchra have fpinous procefTes on both the 

 anterior and poftcrior furfaces ; and the tranfverfe pro- 

 cefTes are ufually very prominent. Tiie hit bone of the 

 tail, is, in mod birds, of a plongh-fliare fhape for the at- 

 tachment of the quills. It is fmall and conic in the r.eiu, 

 loUand ojlrich, and cajfowary ; and in KVe peacock, it is 

 thin, oval, and fituated horizontally. It is wanting in a 

 ▼aricty of the domtlHc oock found in America. 



The fKimim forms one of the moft charattevidic bones 

 in the "ikokton of birds. It is a very broad thin bone, 

 covers tlio anterior part of the common cavity, like a buc- 

 kler, and produces from its middle line, in ever/ bird which 

 is capable of flying, a thin plate of bone, which refembles 

 very much the kctl of a fhip ; but it is moll prominent at 

 its anterior part. Tlie upper edge of the ftcrnum prefents 

 two narrow deprefiions, which receive the ends of tlic two 

 clavicles ; and to the mod anterior point of the keel the 

 fork-fliapcd bone is commonly attached. The poderior 

 edge is thin, and in mod fpecies, contains a fpace on each 

 fide, which is filled with membranes. In the acclpitres, 

 parrot, and mod uqualk birds, this is an oval hole ; but in 

 X\\e gallhi,! it is an oblong vacancy. The keel appears to be 

 added to the dernum, merely for the attachment of the 

 great peftoral mufcle. Accordingly, we find its projec- 

 tion is proportioned to the neccfTity there is for ufing this 

 mufcle during flight ; and in the ojlrkh and cajjo'iuary, 

 which do not employ their wings as organs of locomotion, 

 the keel is abfent, and the dernum is round and fmooth on 

 the external furface, and is very fmall in proportion to the 

 magnitude of thefe birds. 



The r'lhi of birds have been divided, like thofe of mam- 

 malia, into true and falfe, or as Vic d'azir has termed them, 

 the Jlenw-vcrtchral and vertebra/. Tlie true ribs are made 

 of two pieces, which are each compofed of bone : the pof- 

 tcrior portion is affixed to the fpine by means of two 

 branches, of which one is articulated with the body, and 

 the other with the tranfverfe procel's of the fame dorfal 

 vertebra. The anterior piece is articulated by one end, 

 Tvitli t)ie lateral edge of the ftcrnum ; and by the other, to 

 the end of the vertebral portion. The ilcrnal extremities 

 of the ribs, being diftinft bones, deferve to be caWdJlrrnal 

 riir, which term we have employed in oilier parts of this 

 article. MoR. of the true ribs are furnidied, ab.int tl'.eir 

 middle, wit!i a thin offeous procefs, which proceeds ob- 

 liquely baclcwards from the poderior edge of one rib, and 

 over-laps the one next behind it, and fometimcs even goes 

 on to cover two ribs, as in tlie colymbus crt/lafus. The 

 tternal and vertebral portions of the true ribs form, at tlicir 

 junction, an angle which points backwards, and is very 

 acute in the iirtl ribs, which proves that the thorax 

 of birds is chiefly dilated by the anterior part of the dernum, 

 being carried forwards from the dorfal fpine ; at which 

 time, tlie moveable angles of all the ribs become very ob- 

 tufe. Thefe angles are fcarcely obfervable in the Jlrut/jiotis 

 bird'. Their ribs afTume very much the figure of thofe 

 of mammiiHa. 



The number of the derno-vertebral ribs is liable to vary. 

 There are, on each fide, four in the cuckoo and the cajfowary ; 

 Jive 'm the cro'zv, african 'Jlrich, and Jiori j fix in the iittcm ; 



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feven in the eagle, the bii^tard, the oivl, the crane, and tl • 

 duck ; eight in the crejied grebe, and feveral other water- 

 fowl ; and nine in the fwan. 



The -vertebral, or falfe ribs, are in mod birds placed at the 

 anterior part of the thorax, which is the reverfe of what \i 

 obferved in mammalia. When there are any of thefe ribs 

 fituated poderiorly, they arc only one or two pair, aiid im- 

 perfeftly formed ; there are two pair in the Jlrulhious birds, 

 which do not projeft far from the fpine. 



The bones of the pehis become confolidated together at 

 a very early period. Their original parts are therefore very 

 difficult to' didinguifli. The portion correfponding to the 

 cs ilium bears fome refemblance to that bone in mammalia ; 

 but the ifchium and pubis cannot be recognifed by their 

 figure, and are only to be known by their relation to the 

 different foramina. There is a very long, flendtr bone, 

 originally conuefled to the ilium, on the fore-part of the 

 acetabulum, wliich fupplies the place of the pubis. This 

 bone runs parallel to the anterior pavt of the ifchium, with 

 whicli it is occafionally joined towards its extremity, but 

 never unites with the bone of the oppofite fide, except in 

 the oflrich, in which bird the bones of the pubis are broad 

 at their fympbifis, and Hand a little forwards, producmg 

 fomething of the appearance of the pelvis of mammalia. 

 The pubis unites with the ifchium in the accipitres for a con- 

 fiderable way, and leaves a didinft hole analogous to the 

 foramen ovale ; and the fpace between thefe bones pofTLiTes 

 in all birds, at the antenor part, the traces of this fora- 

 men. 



The Ifchium is commonly united to the facrum and back 

 of the ilium, by the part which correfponds to the ifciiiadic 

 /j>ine ; confcquently, the ifchiadic foramen is complete in 

 the fl<eleton of birds. In the oflrich and cajfotuary, how- 

 ever, the ifchium is feparate from the facrum, and is a long, 

 flender dyloid bone, like the pubis. There is no tubero- 

 fity to the ifchium, that part being thin and extended, ex- 

 cept in the oflrich, where it becomes fomcwhat enlarged. 

 The ifchium appears to be joined to the pubis in the new., 

 holland oflrich, by the intervention of another fhort 

 bone. 



The bones of the fhoulder are very peculiar in birds ; 

 befides the clavicles and fcapulx, there is an additional 

 fingle bone, called the fork : it ufually pofTefTes the figure 

 of a V ; the point is attached to the moll anterior part of 

 the keel of the fternum, and the ends of the branches are 

 fecured by a ligament on tlie infide of the dorfal extremities 

 of the clavicles, and alfo to the poderior procefs of the 

 fcapulx, which is analogous to the acromion. The fork 

 frequently approaches more to the figure of an U than a 

 V. Its angle is alfo often at fome diilance from the fter- 

 num, to which it is bound by a ligament. In the gallime, it 

 terminates in a thin plate, from which a ligament is ex- 

 tended to the keel of the fternum. As a general obferva- 

 tion, it may be dated, that the fork is ftroiig and elaftic, 

 and its branches wide, arched, and carried forwards upon 

 the body, in proportion as the bird poU'effes ftrength and 

 rapic'ity of flight ; and accordingly, the flruthious birds, 

 which are incapable of this mode of progrefiion, have the 

 fork very imperfeAly formed. The two branches are very 

 fh rt, and never unite in the africcm oflrich, but are an- 

 chylofed with the fcapulas and clavicle. The caffwMary has 

 merely two little proccffes from the fide of the clavicle 

 which are the rudiments of tke branches of the fork. In 

 the new holland oflrich, there are two very fmall thin 

 bones, which are attached to the anterior edge of the dor- 

 fal end of the clavicles, by hgament ; they are direi'led 

 upwards towards the neck, v.'here they are fa'ftened to each 



other 



