1U TE BONES. 



reciprocal clamping. In this manner, the anterior head of the body of each vertebra is 

 replaced by a facet concave from one side to the other, and convex vertically ; while the 

 posterior extremity of the bone bears, instead of a concavity, a facet convex in the lateral 

 sense, and concave from above to below. The interior crest of the body (fig. 73, 2, 2') 

 only exists in the first and last vertebra? , but it forms a veritable spine, analogous to 

 that observed in the lumbar vertebrae of the rabbit. The spinous process (fig. 73, 1, 1') 

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

 the vertebrae which occupy the two extremities of this region. The transverse process 

 represents on the side of the vertebra a thick, obtuse, and irregular tubercle, situated 

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

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

 (fi^. 73, 3, 3') directed backwards and downwards, forming an epiphysis at%m 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 is received the 

 single condyle of the occipital bone. 



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

 eminence. 



Dorsal vertebrse (Fig. 73. B, o.). These are seven in the Fowl and Pigeon, and nine in 

 the Goose and Duck , they are nearly always consolidated into a single piece to which the 

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

 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 first 

 vertebras. Tne spinous processes, flat, wide, short, and consolidated with each other by 

 their opposite borders, constitute a long crest extending from the last cervical vertebra to 

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

 the fowl they are nearly constantly fused with each other. 



Lumbaj- and sacral vertebra. All these vertebrae 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 vertebrae, 

 numbering fourteen, soon become consolidated with one another and with the ribs; but 

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

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

 the latter in the dorsal region. 



Coccycjeal vertebrx. In the coccygeal region, the spine recovers its mobility. The 

 tail of the bird, indeed, fulfils the office of a rudder 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 right, 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 Jess long on the inferior surface of their bodies. The last vertebra is 

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

 point. 



HEAD (Fig. 73, P. 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 Vertebrae. 6, Spinous process of the first ; 

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

 geal Vertebra;. r, G, Head. 8, Interorbital septum ; 9, Foramen of communica- 

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

 the nose; 11, Maxilla; 12, Square bone; 13, Jugal bone. H, Sternum. 14, 

 Brisket or keel; 1.5, Episternal process; 16, Internal lateral process; 17, Lateral 

 external process; 18, Membrane which closes the internal notch; 19, Membrane 

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

 fifth. J, Inferior ribs; K, Scapula; L, Coracoid bone; M, Furculum. m, 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; s, Ilium; s', Ischium ; s", 

 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. 



