THE ANATOMY OF BIBDH. — OSTEOLOGY. 



147 



The Clavicles, or Furculuni (Lat. clariculn, ii littl(i key : furculiim, a little fork ; 

 figs. 56, 59, d), or the ckivicuUir aroh, arc the pair (jf hones whicli when uuited together form 

 tlie ohjcet well known as the " uicrry-thought " or " wish-hone," corresjKJuding to the human 

 " collar- hones." They lie in front of the breast, across the njiddle line of the hody like a V 

 or U ; the upper ends uniting as a rule both with scapula and coracoid. For this purpose, in 

 most birds, the ends are expanded more or less ; such expansion is called the epideidium (Gr. 

 iit'i, epi, upon ; kXeiSioi/, Ideidion, the collar-bone) ; in Passerine birds it is said to ossify separ- 

 ately, and is considered by Parker to represent the jJi'^coracoid of reptiles. At the point of 

 union below, the hones often develop a process (well shown iu the domestic fowl) called the lnjpo- 

 deidium (Gr. vTrd, hypo, under ; fig. 59, he), supposed to represent the interdavide of reptiles. 

 The clavicles are as a rule present, perfect, anchylosed together, articulated at the shoulder; in a 

 few birds anchylosed there; in several, there and 

 with the keel of the sternum; in Opdsihocomus there 

 and with the manubrium of the sternum. In various 

 birds, chiefly Picarian and Psittaciue, tliey are de- 

 fective, not meeting each other. They are wanting 

 in Struthio, Ehea, Apteryx, and some Psiitadda;. 

 Besides curving tfiward each other, the clavicles 

 have usually a fore-and-aft curvature, convex for- 

 ward. In general, the streugtli of the clavicles, 

 tlie firmness of their conne<-tious, and the openness 

 of the V or U, are indicaticjns of the V(ditorial or 

 natatorial power of the wings. The end of the fur- 

 culuni is hollowed for a fold of the windpipe in the 

 crested pintado (Owen). 



4. THE PELVIC AT!CB. 



The Pelvis (Lat. p>dvis, a basin, fig. 60), is 

 that ])osterior part nf the trunk which receives the 

 uro-genital, and lower portion of the digestive, vis- 

 cera. It consists of the "sacral" vertebra; on tlie 

 middle dorsal line, flanked on each .side by the bones 

 of the pdoic ardi, which supports the hind limb. 

 In vertebrates generally the pelvic basin is com- 

 pleted on the ventral a.spect by union (sympliysis ; 

 Gr. cTvv, nun, together ; (piats, growth) of the bones 

 from opposite sides. Excepting only Stmthio, which 

 has a pubic symphysis ; and MJiea, whicli lias an 

 ischiac symphysis just below the sacral vertebrae, 

 the pelvis of a bird is entirely open below and 

 behind ; each pelvic arch anchylosing firmly with 

 the sacral vertebree to form a roof over the viscera 

 above named. This sacrfi-iliac anchylosis is com- 

 monly coextensive with the confluence of the many 

 vertebraB which make the "sacrum" of ordinary 

 language, that is, from the first dorso-lumbar to the 

 last uro-sacral. The whole roof-like affair looks 

 something like a keelless stenium inverted. The 

 pelvic arch of each side consists of three bones, ilium, 



Fig. 60, — Pelvi.s of a heron {Ardf^a herndiaa), 

 n.it. size, viewed from lielow ; from nature by Tir. 

 K. W. SlmfeUU, U.S.A. dl, dorso-lumbar vertebrse 

 to and inelu<]ing tlie last one, sc ; below sc, for the 

 extentof the/rtri7pblackspaces(opp08itetliearrow) 

 are the true sncral vertebras; ?(.t, uropacral verte- 

 bral (opposite the five oval black spaces ; It, ilium ; 

 la, ischium; P, pubis; oh, obturator forameo. 

 The arrow flies into the acetabulum. 



