114 v///: PGWBS 



reciprocal clamping. In this manner, the anterior head of the body 'f < ; "h v. rd lira in 

 replaced 1'v a taivt coiu-ave from one side to the- other, and ron\ ( -\ \, iticully : whili- the 



posterior extremity of the bone bears, instead of a concavity, a facet < vex in tin lateral 



sense, and concave from above to helow. The interior i-n-.-t of tin ln.lv (Ik-. 7::. '2. '2 ) 

 only exibts in t lie first and last vertebrro; but it forms a veritaMe H]HH. annl.i 

 that observed in the lumbar vertebra) of the rabbit. The spinous proe. . 1, 1') 



only forms a simple crest in the middle part of the neck; it becomes more salient in 

 the vertebra) which occupy the two extremities of this region. The; tnin>\ 

 represent;* on the side of the vertebra a thick, obtuse, and irregular tulx-rcle, .-itu :1 t d 

 under the anterior articular process, and pierced at its base by a largo vertebral foramen 

 (fig. 73, 4, 4'). It is most frequently furnished with a small styloid prolongation 

 (fig. 73, 3, 3') directed backwards and downwards, forming an epiphysis at an early 

 period, and representing a real undeveloped rib. 



The atlas has no transverse processes. This vertebra is shaped like a thin ring, 

 and is excavated on its anterior contour by a small cavity into which u received the, 

 single condyle of the occipital bone. 



The axis shows a very marked odontoid process with a single facet under that 

 eminence. 



Dorsal vertebra (Fig. 73 u, c.). These are seven in the Fowl and PtV/eon, and nine in 

 the Goose and Duck ; they are nearly always consolidated intoa single piece to which the 

 trunk is fixed, and which gives the wings a solid support in the violent efforts that llight 

 demands. The two or three last are often even covered by the wing-bones, and joined 

 to them. The inferior crest of the body forms a very long spine, especially in the tir-t 

 vertebrae. Tne spinous processes, flat, wide, short, and consolidated with ta:-h other l.y 

 their opposite borders, constitute a long crest extending fiom the lust cervical \vrteb: a to 

 the bones of the wings (tig. 73, 7). Tne transverse processes widen to their summit ; in 

 the fowl they are nearly constantly fused with each other. 



Lumbar and sacral vertebra". All these vertebra) are formed exactly on the same 

 type; so that it becomes difficult, if not impossible, to fix the point where the lumbar 

 region ends or the sacral begins. At first independent of each other, these vertebras, 

 numbering fourteen, soon become consolidated with one another a-ul with the ribs; but 

 their primitive separation is always indicated by the lateral M pta which form, on their 

 inferior face, the vestiges of the transverse processes. The former are closely united to 

 the latter in the dorsal region. 



Coccygeal vertebra. In the coccygeal region, the spine recovers its mobility. The 

 tail of the bird, indeed, fulfils the office of a rud ler to direct it during flight ; and it is 

 absolutely necessary that the vertebrae which serve as a base for the steering feathers 

 should preserve their independence, so as to allow these to be carried to the riglit, left, 

 downwards, or upwards. These vertebrae, seven in number, present spinous processes 

 which are often bifurcated, transverse processes very developed, and sometimes even 

 spines more or less long on the inferior surface of their bodies. The Inst vertebra is 

 always the most voluminous; it is flattened on both sides, and terminates in a curved-up 

 point. 



HEAD (Fig. 73, F. G.). The head of the bird is small, and of a conical form. The 

 anterior extremity is elongated, and terminated by a pointed or flattened beak, which 

 allows the animal to cut the air with more facility. 



the same; 4, Vertebral foramen of the same; 1', 2', 3', 4', The same parts in the 

 twelfth vertebra. From B to C, Dorsal Vertebra:. 6, Spinous process of the tirst ; 

 7, Crest formed by the union of the other spinous processes. From D to K, Coccy- 

 geal Vertebras. F, o, Head. 8, Interorbital septum ; 9, Foramen of communica- 

 tion between the two orbits; 10, Prumaxillary bone; 10', External openings of 

 the nose; 11, Maxilla; 12, Square bone; l.'J, Jugal bone. u, Sternum. 14, 

 Brisket or keel; 15, Episternal process; 1(5, Internal lateral process; 17, Literal 

 external process; 18, Membrane which closes the intiTii.il notch; 111, Meinhnnn: 

 of tne external notch. I, etc., Superior Ribs. 20, Posterior process of the 

 fifth. J, Inferior ribs; K, Scapula; L, Coracoid bone; M, Furculum. w, m, Its 

 two branches. N, Humerus; o, Ulna. o, Radius. p, p', Bones of carpus; 

 Q, Q', Bones of metacarpus; R, First phalanx of the large digit of the wing. r, 

 Second phalanx of the same. R', Phalanx of thumb; 8, Ilium; s', Ischium ; 8", 

 Pubis. 21, Sciatic foramen; 22, Foramen ovale. T, Femur; u, Patella; V, 

 Tibia ; x, Fibula. y, Single bone of tarsus. Y, Metatarsus. 23, Superior process 

 representing a united metatarsal bone; 24, Process supporting the claw. 

 z, etc., Digits. 



